B.Sc. (Tsinghua University), M.Sc., Ph.D. (Massachusetts Institute of Technology), P.Eng.
Group IV semiconductors in microelectronics, Ge-on-Si lasers, 2D semiconductors, 3D integration of ICs, Raman spectroscopy
Current Research Work
General Group Overview
The advancement in semiconductor materials, devices and fabrication techniques has been one of the most important driving forces for the ever-changing Information Age and the Internet of Things (IoT). My research has focused on semiconductors to make smaller, faster, lower-cost and more energy efficient computation and communication hardware. My most recent research areas are given below:
Group IV semiconductors in microelectronics
To further advance the performance of microelectronic devices such as CMOS and HBTs, group IV elements and alloys such as germanium (Ge), SiGe, SiGe:C and GeSn are integrated into silicon platforms to boost performance by stress, bandgap and defect engineering. The integration of these new materials, especially with the increasing Ge, Sn or C fractions and the resulting stresses, introduces new process phenomena and fabrication challenges such as dopant diffusion and segregation, Si-Ge interdiffusion, Ge-Sn interdiffusion, stress-diffusion interaction etc. We investigate these new phenomena experimentally, catch them in mathematical models and implement in TCAD simulation tools to assist industry in structure and fabrication design of these devices.
Our Si-Ge interdiffusion data and models have been widely used and implemented in the state-of-the-art process simulation tools including Intel R&D’s in-house process simulation tool, Crosslight Software’s CSUPREMTM and Synopsys’s Sentaurus ProcessTM (the leading commercial 3D process simulation tool in the semiconductor industry), and Lumerical’s DEVICETM for structure and process design of next generations of semiconductor device. Our work on dopant profile engineering has been used extensively by the Analog Technology team of Texas Instruments.
Integrating optical functions with Si-based microelectronics has been a long dream for the semiconductor industry to reduce cost and increase packaging density.
A major challenge in realizing thisdream has been in finding Si-compatible light sources, especially lasers. Our work first demonstrated the successful integration of AlGaAs distributed Bragg reflectors (DBRs) on on-axis Si (100) substrates via a Ge layer formed by aspect ratio trapping (ART) technique (Fig. 2). The DBRs were grown by LandMark, our supporting organization in Taiwan. The GaAs/ART-Ge/Si-based DBRs have reflectivity spectra comparable to those grown on conventional bulk GaAs substrates (Fig. 3) and have smooth morphology, good periodicity and uniformity. Anit-phase domain formation is significantly reduced in these substrates, and threading dislocation density of the GaAs layer shown was 105 to 6 × 106 cm-2. These paved the way for the successful full VCSEL growth and fabrication on GaAs/ART-Ge/Si substrates. We are currently working on full VCSELs on GaAs/Ge/Si substrates in collaboration with Prof. Chiao-hsin Wu at National Taiwan University and LandMark Optoelectronics.
Our recent work studied the impacts of dopants and annealing on Si-Ge interdiffusion and the Ge film quality for Ge-on-Si structures including surface roughness, etch pit density, interdiffusion and photoluminescence with the collaboration with Prof. Jifeng Liu (Dartmouth College) and Dr. Kwang Hong Lee and Prof. Chuan Seng Tan (Nanyang Technological University). The un-annealed P or As-doped Ge films have similar photoluminescence intensity at a 25% doping concentration and smoother surface compared with the first Ge laser work by MIT in 2012, which are promising for Ge lasers with better light emission efficiencies.
On the device modeling and simulation side, we focused on addressing the potential and optimization of Ge-on-Si lasers with 2D stress and laser modeling and simulations. Ge-on-Si lasers are another important option for Si-compatible lasers with the advantages of easy integration and fabrication with Si-based microelectronics and thus much lower fabrication cost and shorter time to deployment. Our studies showed that with laser structure optimization and stress engineering, a wall-plug efficiency of 30% can be achieved with currently available Ge growth techniques, which are tremendous improvements from the available experimental value of about 0.1%. Considering that common commercial compound semiconductor lasers have wall-plug efficiencies in the range of 20-30%, our studies strongly support Ge-on-Si lasers and gave guidance for future improvements.
GaN power devices
AlGaN/GaN-based high electron mobility transistors (HEMTs) have been under extensive research for their high breakdown voltage, good thermal stability and low noise performance. We investigate multiple aspects of GaN HEMTs including approaches in realizing enhancement-mode GaN HEMTs and in forming low resistance contacts. These efforts are in collaboration with Prof. Hongyu Yu at South University of Science and Technology, China and Enkris Semiconductor, China.
2D semiconductors are suitable for thin, quasi-transparent and flexible electronics and photonics. Black phosphorus was successfully isolated in 2013 and was shown to have unique properties such as direct and tunable bandgap from 0.3 to 2 eV, suitable for applications in thermal imaging, photovoltaics and telecomm. We investigate the fabrication and properties of single to few-layer black phosphorus.
With a new polycarbonate-film-based dry transfer method, we successfully fabricated twisted stacked few-layer black phosphorus. Optical characterization showed the overlapping area had special optical response, and high frequency Raman spectroscopy showed an abnormal blue shift in Ag1 and Ag2 modes. Density functional theory (DFT) calculations confirmed this blue shift in twisted bilayer black phosphorus, and revealed significant interlayer coupling effects. Charge distribution calculations indicated weak valence bond may exist between the two layers. This finding may lead to applications in phonon modulation and gate switchable transportation.
3D integration of ICs
Through-silicon-via (TSV) is a key element for 3-D integration in providing vertical interconnects for chip-stacking structures. Thermal-mechanical stress originating from the thermal expansion coefficient mismatch of Cu and Si can cause uniformity and reliability issues. We study the stress distribution around Cu-filled and carbon-nanotubes-filled TSVs, its influencing factors and the impact on carrier mobility and keep-out zone (KOZ) for logic devices near the TSVs, which is important for the design and reliability of 3D integrated circuits. These efforts are in collaboration with Prof. Chuan Seng Tan at Nanyang Technological University.
Raman spectroscopy applications in semiconductors
Micro-Raman spectroscopy is a powerful tool in studying chemical concentration, stress, crystallinity, chemical bonding, crystal orientation, phases and temperature. We have the capability of doing in-situ Raman during thermal treatments. The material systems we studied include Ge, SiGe, SiGe:C alloys, Ge nanowires, InGaAs/GaAs, carbon nanotubes, graphene, nanocrystalline Si, black phosphorus, FinFETs, Ti oxide and soils.
Current and Recent Projects
- Enhance-mode GaN HEMTs with metal/2D material gates
- La-based GaN S/D contacts and gate contacts
- i-GaN and MIS-gate for GaN HEMTs
- Vertical doping profile control for PNP and NPN SiGe HBTs
- Doping effects on Si-Ge interdiffusion and on epitaxial Ge film quality
- Fabrication and Raman response of twisted stacked few-layer black phosphorus
- Stress engineering and fabrication of Ge-on-Si lasers
- Stress field around Cu and CNT-filled TSVs
- High resolution confocal micro-Raman LabRam HR by Horiba Scientific
- AMPEL nanofabrication facility
Computational software packages
- TSUPREM-4, Medici, Sentaurus Process by Synopsys
- LASTIP, CSUPREM, APSYS by Crosslight Software
- INTERCONNECTS by Lumerical Solutions
Recent work archived:
1. Study of Black Phosphorus Using Angle-Resolved Polarized Raman Spectroscopy with 442 nm Excitation
Authors: Weijun Luo, Qian Song, Guangnan Zhou, David Tuschel, and Guangrui (Maggie) Xia
2. A wet etching method for few-layer black phosphorus with an atomic accuracy and compatibility with major lithography techniques
Authors: Teren Liu, Tao Fang, Karen Kavanagh, Guangrui (Maggie) Xia
3. Silicon Nitride Stress Liner Impacts on the Electrical Characteristics of AlGaN/GaN HEMTs
Authors: Wei-Chih Cheng, Tao Fang, Siqi Lei, Yunlong Zhao, Minghao He, Mansun Chan, Guangrui (Maggie) Xia, Feng Zhao, Hongyu Yu
Refereed Journal Papers
- Liang Wang, Guangrui (Maggie) Xia and Hongyu Yu, “A Method to Determine Broadband Complex Permittivity of Thin Film Dielectric Materials“, IEEE Transactions on Electromagnetic Compatibility, published online in May 2020, doi: 10.1109/TEMC.2020.2989227.
- [Reported in Semiconductor Today] Wei-Chi Cheng, Minghao He, Siqi Lei, Liang Wang, Liang, Jingyin Wu, Fangming Zeng, Qiaoyu Hu, Qing Wang, Feng Zhao, Mansun Chan, Guangrui Xia, and Hongyu Yu, “Increasing Threshold Voltage and Reducing Leakage of AlGaN/GaN HEMTs Using Dual-Layer SiNx Stressors“, Semiconductor Science and Technology, vol. 35, p. 045010, 2020. Related report in Semiconductor Today: http://www.semiconductor-today.com/news_items/2020/apr/sustech-230420.shtml
- Guangnan Zhou, Zeyu Wan, Gaiying Yang, Yang Jiang, Robert Sokolovskij, Hongyu Yu, and Guangrui (Maggie) Xia, “Gate Leakage Suppression and Breakdown Voltage Enhancement in p-GaN HEMTs using Metal/Graphene Gates”, IEEE Transactions on Electron Devices, vol. 67, pp. 875-880, 2020.
- Siqi Lei, Wei-Chih Cheng, Jingyi Wu, Liang Wang, Qing Wang, Guangrui (Maggie) Xia, Feng Zhao and Hongyu Yu, “Low Leakage GaN HEMTs with Sub-100 nm T-shape Gates Fabricated by a Low-damage Etching Process“, Journal of Materials Science: Materials in Electronics, vol. 31, pp.5886–5891, 2020.
- [Editor’s Pick] Guangnan Zhou, Alejandra V. Cuervo Covian, Kwang Hong Lee, Han Han, Chuan Seng Tan, Jifeng Liu, and Guangrui (Maggie) Xia, “Improved Thin Film Quality and Photoluminescence of N-Doped Epitaxial Germanium-on-Silicon using MOCVD“, Optical Materials Express, vol. 10, 2019, pp. 1-13.
- Jingyi Wu, Siqi Lei, Wei-Chih Cheng, Robert Sokolovskij, Qing Wang, Guangrui (Maggie) Xia, and Hongyu Yu, “Oxygen-based digital etching of AlGaN/GaN structures with AlN as etchstop layers“, Journal of Vacuum Science and Technology A, vol. 37, 2019, p. 060401 (4pp).
- [Review] Guangrui (Maggie) Xia, “Interdiffusion in Group IV Semiconductor Material Systems: Applications, Research Methods and Discoveries“, Science Bulletin, vol. 64, 2019, pp. 1436-1455.
- Tao Fang, Teren Liu, Zenan Jiang, Rui Yang, Peyman Servati and Guangrui (Maggie) Xia, “Fabrication and the Interlayer Coupling Effect of Twisted Stacked Black Phosphorus for Optical Applications“, ACS Applied Nano Materials, vol. 2, 2019, pp. 3138-3145.
- Rui Yang, Weijun Luo, Shun Chi, Douglas Bonn and Guangrui (Maggie) Xia, “The stability of exfoliated FeSe nanosheets during in-air device fabrication processes“, IEEE Transactions on Nanotechnology, vol. 18, 2019, p.37.
- Guangnan Zhou, Kwang Hong Lee, Dalaver H. Anjum, Qiang Zhang, Xixiang Zhang, Chuan Seng Tan and Guangrui (Maggie) Xia, “Impacts of Doping on Epitaxial Germanium Thin Film Quality and Si-Ge Interdiffusion”, Optical Materials Express, vol. 8, Issue 5, 2018, pp. 1117-1131.
- Weijun Luo, Rui Yang, Jialun Liu, Yunlong Zhao, Wenjuan Zhu, and Guangrui (Maggie) Xia, “Thermal Sublimation: a Scalable and Controllable Thinning Method for the Fabrication of Few-Layer Black Phosphorus“, Nanotechnology, vol. 28, 2017, p.285301 (12pp).
- Jiaxin Ke, Lukas Chrostowski and Guangrui (Maggie) Xia, “Stress engineering with silicon nitride stressors for Ge-on-Si lasers“, IEEE Journal of Photonics, vol. 9, 2017, pp. 0-14.
- [Editor’s Pick] Yiheng Lin, Wei Shi, Jizhong Li, Ting-Chang Chang, Ji-Soo Park, Jennifer Hydrick, Zigang Duan, Mark Greenberg, James G. Fiorenza, Lukas Chrostowski and Guangrui (Maggie) Xia, “Monolithic Integration of AlGaAs Distributed Bragg Reflectors on Virtual Ge Substrates via Aspect Ratio Trapping“, Optical Materials Express, vol. 7, 2017, pp. 726-733.
- Colton Wells, Jheng-Yi Jiang, Ting-Fu Chang, Chih-Fang Huang, Jiaxin Ke, Weijun Luo, Guangrui Xia, Kuan Yew Cheong, and Feng Zhao, “Stress and thermal characterization of 4H-SiC microelectromechanical structures“, Materials Letters, vol. 191, 2017, pp. 196–199.
- Feiyang Cai, Dalaver H. Anjum, Xixiang Zhang and Guangrui (Maggie) Xia, “Study of Si-Ge Interdiffusion with Phosphorus Doping“, Journal of Applied Physics, vol. 120, 2016, p. 165108 (10 pages).
- Xiyue Li, Zhiqiang Li, Simon Li, Lukas Chrostowski and Guangrui (Maggie) Xia, “Design Considerations of Biaxially Tensile-Strained Germanium-on-Silicon Lasers“, Semiconductor Science and Technology, vol. 31, 2016, p. 065015.
- Ye Zhu, Kaushik Ghosh, Hong Yu Li, Yiheng Lin, Chuan Seng Tan, Guangrui (Maggie) Xia, “On the Origins of Near-Surface Stresses in Silicon around Cu-filled and CNT-filled Through Silicon Vias“, Semiconductor Science and Technology, vol. 31, 2016, p. 055008.
- S. Arash Sheikholeslam, Weijun Luo, Cristian Grecu, Guangrui (Maggie) Xia and André Ivanov, “Hydrogen diffusion in amorphous ZrO2”, Journal of Non-crystalline Solids, vol. 440, May 2016, pp. 7–11.
- Hung Nguyen, Chih-Fang Huang, Weijun Luo, Guangrui (Maggie) Xia, Zhiqiang Chen, Zhiqiang Li, Christopher Raymond, David Doyle, Feng Zhao, “Synthesis of Large-Scale 2-D MoS2 Atomic Layers by Hydrogen-free and Promoter-free Chemical Vapor Deposition”, Materials Letters, vol. 168, April 2016, pp. 1-4.
- Yiheng Lin, Hiroshi Yasuda, Manfred Schiekofer and Guangrui (Maggie) Xia, “The Effects of Thermal Nitridation on Phosphorus Diffusion in Strained SiGe and SiGe:C“, Journal of Materials Science, vol. 51, Feb. 2016, pp. 1532-1540.
- S. Arash Sheikholeslam, Guangrui (Maggie) Xia, Cristian Grecu, Andre Ivanov, “Generation and properties of bulk α-ZrO2 by molecular dynamics simulations with a reactive force field”, Thin Solid Films, vol. 594, Nov. 2015, pp. 172–177.
- Feiyang Cai,Yuanwei Dong, Yew Heng Tan, Chuan Seng Tan and Guangrui (Maggie) Xia,“Enhanced Ge-Si Interdiffusion in High Phosphorus-Doped Germanium on Silicon”, Semiconductor Science and Technology, vol. 30, 2015, p. 105008.
- Yiheng Lin, Hiroshi Yasuda, Manfred Schiekofer and Guangrui (Maggie) Xia, “Coupled Dopant Diffusion and Segregation in Inhomogeneous SiGe Alloys: Experiments and Modeling”, J. Appl. Phys., vol. 117, 2015, pp. 214901-1 to 214901-7.
- Ye Zhu, Jiye Zhang, Hong Yu Li, Chuan Seng Tan and Guangrui (Maggie) Xia,”Study of Near-surface Stresses in Silicon around Through Silicon Vias at Elevated Temperatures by Raman spectroscopy and Simulations”, IEEE Transactions on Device and Material Reliability, vol. 15, 2015, pp.142-148.
- Yiheng Lin, Hiroshi Yasuda, Manfred Schiekofer, Bernhard Benna, Rick Wise and Guangrui (Maggie) Xia, “Effects of Carbon on Phosphorus Diffusion in SiGe:C and the Implications on Phosphorus Diffusion Mechanisms”, J. Appl. Phys, vol. 116, 2014, pp.144904-1 to 144904-9.
- Yuanwei Dong, Patricia M Mooney, Feiyang Cai, Dalaver Anjum, Naeem Ur-Rehman, Xixiang Zhang and Guangrui (Maggie) Xia, “Experiments and Modeling of Si-Ge Interdiffusion with Partial Strain Relaxation in Epitaxial SiGe Heterostructures”, ECS Journal of Solid State Science and Technology, vol.3, 2014, p.302-p.309.
- K. J. Schmidt, Y. Lin, M. Beaudoin, G. Xia, S. K. O’Leary, G. Yue, and B. Yan, “The mean crystallite size within a hydrogenated nanocrystalline silicon based photovoltaic solar cell and its role in determining the corresponding crystalline volume fraction”, Canadian Journal of Physics, vol. 92, 2014.
- Yuanwei Dong, Winston Chern, Patricia M Mooney, Judy L Hoyt and Guangrui (Maggie) Xia, “On the role and modeling of compressive strain in Si-Ge interdiffusion for SiGe heterostructures”, Semiconductor Science and Technology, vol. 29, 2014, pp. 015012
- Kaushik Ghosh, Jiye Zhang, Lin Zhang, Yuanwei Dong, Hongyu Li, Cher Ming Tan, Guangrui Xia, and Chuan Seng Tan, “Integration of Low-Dielectric Liner in Through Silicon Via and Thermomechanical Stress Relief”, Applied Physics Express vol. 5, 2012, pp. 126601-1 to 126601-3.
- Yuanwei Dong, Yiheng Lin, Simon Li, Steve McCoy, and Guangrui (Maggie) Xia, “A unified interdiffusivity model and model verification for tensile and relaxed SiGe interdiffusion over the full germanium content range”, J. Appl. Phys. Vol. 111, 2012, pp. 044909-1 to 044909-9
- Chih-Hao Dai,Ting-Chang Chang, Ann-Kuo Chu, Yuan-Jui Kuo, Szu-Han Ho, Tien-Yu Hsieh,Wen-Hung Lo, Ching-En Chen, Jou-Miao Shih, Wan-Lin Chung, Bai-Shan Dai, Hua-Mao Chen, Guangrui Xia, Osbert Cheng, and Cheng Tung Huang, “Hot carrier effect on gate-induced drain leakage current in high-k/metal gate n-channel metal-oxide-semiconductor field-effect transistors”, Applied Physics Letters, vol. 99, 2011, pp. 012106-1 to 012106-3.
- Chih-Hao Dai, Ting-Chang Chang, An-Kuo Chu, Yuan-Jui Kuo, Fu-Yen Jian, Wen-Hung Lo, Szu-Han Ho, Ching-En Chen, Wan-Lin Chung, Jou-Miao Shih, Guangrui Xia, Osbert Cheng, and Cheng-Tung Huang, “On the Origin of Gate-Induced Floating-Body Effect in PD SOI p-MOSFETs”, IEEE Electron Device Letters, vol. 32, No. 7, 2011, pp. 847-849.
- Chih-Hao Dai,Ting-Chang Chang, Ann-Kuo Chu, Yuan-Jui Kuo, Wen-Hung Lo, Szu-Han Ho, Ching-En Chen, Jou-Miao Shih, Hua-Mao Chen, Bai-Shan Dai, Guangrui Xia, Osbert Cheng, and Cheng Tung Huang, “Impact of static and dynamic stress on threshold voltage instability in high-k/metal gate n-channel metal-oxide-semiconductor ﬁeld-effect transistors”, Applied Physics Letters, vol. 98, 2011, pp. 092112-1 to 092112-3.
- Chih-Hao Dai, Ting-Chang Chang, Ann-Kuo Chu, Yuan-Jui Kuo, Shih-Ching Chen, Chih-Tsung Tsai, Wen-Hung Lo, Szu-Han Ho, Guangrui Xia, Osbert Cheng, Cheng Tung Huang, “Enhanced gate-induced foating-body effect in PD SOI MOSFET under external mechanical strain”, Surface & Coatings Technology, vol. 205, 2010, pp. 1470-1474.
- Chih-Hao Dai, Ting-Chang Chang, Ann-Kuo Chu, Yuan-Jui Kuo, Shih-Ching Chen, Chih-Chung Tsai, Szu-Han Ho, Wen-Hung Lo, Guangrui Xia, Cheng, Osbert Cheng and Cheng Tung Huang, “On the Origin of Hole Valence Band Injection on GIFBE in PD SOI n-MOSFETs”, IEEE Electron Device Letters, vol. 31, 2010, pp. 540-542.
- Guangrui Xia and Judy L. Hoyt, “Si-Ge Interdiffusion under Oxidizing Conditions in Epitaxial SiGe Heterostructures with High Compressive Stress,” Applied Physics Letters, vol. 96, 2010, pp. 122107-1 to 122107-3.
- Guangrui Xia, Michael Canonico, and Judy L. Hoyt, “Si–Ge interdiffusion in strained Si/strained SiGe heterostructures and implications for enhanced mobility metal-oxide-semiconductor field-effect transistors,” Journal of Applied Physics, vol.101, 2007, pp. 044901-1 to 044901-11.
- Guangrui Xia, Michael Canonico, and Judy L. Hoyt, “Interdiffusion in strained Si/Strained SiGe epitaxial heterostructures,” Semiconductor Science and Technology, vol.22, 2006, S55–S58
- Guangrui Xia, Michael Canonico, O. O. Olubuyide and Judy L. Hoyt, “Strain dependence of Si-Ge interdiffusion in epitaxial Si/Si1-yGey/Si heterostructures on relaxed Si1-xGex substrates,” Applied Physics Letters, vol. 88, 2006, pp. 013507-1 to 013507-3.
- J. Li, D. Anjum, R. Hull, Guangrui Xia and J. L. Hoyt, “Nanoscale stress analysis of strained-Si metal-oxide-semiconductor field-effect transistors by quantitative electron diffraction contrast imaging,” Applied Physics Letters, vol. 87, no. 22, 2005, pp. 222111-1 to 222111-3.
- Guangrui Xia, H. M. Nayfeh, M. L. Lee, E. A. Fitzgerald, D. A. Antoniadis, D. H. Anjum, J. Li, R. Hull, N. Klymko, and J. L. Hoyt, “Impact of ion implantation damage and thermal budget on mobility enhancement in strained-Si N-channel MOSFETs,” IEEE Transactions on Electron Devices, vol. 51, no. 12, December 2004, pp. 2136-2144.
- F. Z. Cui, Z. J. Chen, J. Ma, Guangrui Xia, Y. Zhai, “Atomistic simulation of radiation damage to carbon nanotube,” Physics Letters A, vol. 295, no. 1, March 11, 2002, pp. 55-59.
- M.L. Swiggers, Guangrui Xia, J.D. Slinker, A.A. Gorodetsky, G.G. Malliaras, R.L. Headrick, Brian T. Weslowski, R.N. Shashidhar and C.S. Dulcey, “Orientation of pentacene films using surface alignment layers and its influence on thin-film transistor characteristics,” Applied Physics Letters, vol. 79, no. 9, August 27, 2001, pp. 1300.
- Fuzhai Cui, Guangrui Xia and An Chen, “Atomistic simulation of radiation damage to carbon nanotubes,” Progress in Natural Science, vol. 10, no. 3, 2000, pp. 278-281.
Invited Conference Presentations
- Guangrui (Maggie) Xia, “Processing modeling in SiGe Devices”, at the 23rd annual International Conference on Simulation of Semiconductor Processes and Devices conference (SISPAD), Austin, Texas in Sep. 2018. SISPAD is one of the longest-running conferences devoted to technology computer-aided design (TCAD), advanced modeling of novel semiconductor devices, and nano-electronic structures.
- Guangrui (Maggie) Xia, “Dopant diffusion and segregation, Si-Ge interdiffusion and defect engineering in SiGe devices“, the 47th European Solid-State Device Research Conference and the European Solid-State Circuits Conference (ESSDERC/ESSCIRC), Leuven Belgium, Sep. 2017. ESSDERC and ESSCIRC are the prime European conferences on nano-electronics technology and design.
- Guangnan Zhou, Lee Kwang Hong, Chuan Seng Tan and Guangrui (Maggie) Xia, “Impacts of Doping on Ge Thin Film Quality and Si-Ge Interdiffusion”, Photonics North 2017, Ottawa ON, Canada, June 2017
- Guangrui Xia, “Ge lasers: performance, potential and roadmap”, Photonics North 2016, Qubec City QC, Canada, May 2016.
- Guanguri Xia “Interdiffusion and dopant diffusion in SiGe and SiGe:C systems”, 16th Canadian Semiconductor Science and Technology Conference, Thunderbay ON, Canada, August 2013
Contributed Conference Presentations and Papers
- Guangnan Zhou, Kwang Hong Lee, Dalaver H. Anjum, Qiang Zhang, Xixiang Zhang, Chuan Seng Tan and Guangrui (Maggie) Xia, “Growth, Material Quality and Si-Ge Interdiffusion in Doped Ge/Si”, the 9th International SiGe Technology and Device Meeting (ISTDM), Potsdam, Germany, May 2018.
- Tao Fang, Teren Liu, Zenan Jiang, Rui Yang, Peyman Servati, Joshua Folk, Mona Berciu and Guangrui (Maggie) Xia, “Observation of abnormal blue shift in Raman spectra for twisted few-layer black phosphorus”, the 9th International SiGe Technology and Device Meeting (ISTDM), Potsdam Germany, May 2018.
- Tao Fang, Rui Yang, Zenan Jiang, Teren Liu, Peyman Servati, Joshua Folk, Mona Berciu and Guangrui (Maggie) Xia, “Fabrication of twisted stacked black phosphorus“, accepted for oral presenation at American Physics Society March Meeting 2018, Session P36, Los Angeles, CA, USA
- Weijun Luo, Qian Song, Guangnan Zhou, David Tuschel, Guangrui Xia, “Study of Black Phosphorus Using Angle-Resolved Polarized Raman Spectroscopy with 442 nm Excitation”, 18th Canadian Semiconductor Science and Technology Conference, Sep. 2017.
- Weijun Luo, Rui Yang, Jialun Liu, Wenjuan Zhu, Guangrui (Maggie) Xia, “Thermal Sublimation as a Scalable and Controllable Thinning Method for the Fabrication of Few-Layer Black Phosphorus”, Materials Research Society 2016 Fall Meeting, Boston, MA, USA, Nov. 27 – Dec. 2, 2016.
- Jiaxin Ke, Zhiqiang (Leo) Li, Simon Li, Guangrui (Maggie) Xia, “Stress and structure optimizations with side silicon nitride stressors for Ge-on-Si lasers”, Advanced Photonics Congress, Vancouver BC, Canada, July 2016
- Xiyue Li, Zhiqiang Li, Simon Li, Bin Li, Guangrui Xia, “Temperature Characteristics of Tensile-Strained Ge-on-Si Lasers”, International SiGe Technology and Device Meeting 2016, Nagoya, Japan, June 2016
- Feiyang Cai, Dalaver H. Anjum, Xixiang Zhang, Guangrui (Maggie) Xia, “Experiments and Quantitative Modeling of Si-Ge Interdiffusion with High Phosphorus Doping”, accepted for presentation at International SiGe Technology and Device Meeting 2016, Nagoya, Japan, June 2016
- Xiyue Li, Zhiqiang Li, Simon Li, Lukas Chrostowski, and Guangrui (Maggie) Xia, “Design Optimizations of Biaxially Tensile-Strained Germanium-on-Silicon Lasers”, 17th Canadian Semiconductor Science and Technology Conference, Sherbrook, Canada, August 2015
- Ye Zhu, Kaushik Ghosh, Hong Yu Li, Yiheng Lin, Yingbin Qiu, Gao Sheng, Feiyang Cai, Chuan Seng Tan and Guangrui (Maggie) Xia, “On the Origins of Near-Surface Stresses in Silicon around Cu-filled and CNT-filled Through Silicon Vias”, 17th Canadian Semiconductor Science and Technology Conference, Sherbrook, Canada, August 2015
- Feiyang Cai, Simon Li, Fred Fu and Guangrui Xia, “Modeling of Reverse Gate Leakage Current for AlGaN/GaN HEMTs”, Conference on Electron Devices and Solid-State Circuits (EDSSC), June 2015, Singapore.
- Yiheng Lin, Hiroshi Yasuda, Manfred Schiekofer, Bernhard Benna and Guangrui Xia,“Effect of Thermal Nitridation on Phosphorus Diffusion in SiGe and SiGe:C and Its Implication on Diffusion Mechanism”, 7th International Silicon-Germanium Technology and Device Meeting, June 2014, Singapore.
- J. Zhang, L. Zhang, Y. Dong, H.Y. Li, C. M. Tan, G. Xia, and C. S. Tan, “The dependency of TSV keep-out zone (KOZ) on Si crystal direction and liner material,” IEEE International 3D System Integration Conference (3DIC), San Francisco, October 2013.
- Kathrin J. Schmidt, Yiheng Lin, Mario Beaudoin, Guangrui Xia, Stephen K. O’Leary, Guozhen Yue, and Baojie Yan, “Correlation of material structure and solar cell device performance in hydrogenated nanocrystalline silicon solar cells”, Materials Research Society Spring Meeting 2013.
- Winston Chern, Pouya Hashemi, James T. Teherani, Tao Yu, Yuanwei Dong, Guangrui Xia,Dimitri A. Antoniadis, and Judy L. Hoyt, “High Mobility High-κ-All-Around Asymmetrically-Strained Germanium Nanowire Trigate p-MOSFETs”, IEEE International Electron Devices Meeting(IEDM), San Francisco, Dec. 2012.
- J. Zhang, K. Ghosh, L. Zhang, Yuanwei Dong, H.Y. Li, C. M. Tan, Guangrui Xia, and C. S. Tan, “TSV Scaling with Constant Liner Thickness and the Related Implications on Thermo-mechanical Stress, Capacitance, and Leakage Current,” International Conference on Solid State Devices and Materials (SSDM), Kyoto, Japan, September 25-27, 2012.
- K. Ghosh, J. Zhang, L. Zhang, Yuanwei Dong, H.Y. Li, C. M. Tan, Guangrui Xia, and C. S. Tan, “Strategy for TSV Scaling with Consideration on Thermo-mechanical Stress and Acceptable Delay,” International Microsystems, Packaging, Assembly Circuits Technology Conference (IMPACT), Taipei, Taiwan, October 24-26, 2012.
- Yuanwei Dong, and Guangrui Xia, “Modeling of SiGe Interdiffusion over the Full Germanium Content Range”, 15th Canadian Semiconductor Science and Technology Conference, Vancouver, Canada, August 2011
- Yiheng Lin, Wei Shi, Jizhong Li, Ting-Chang Chang, Ji-Soo Park, Jennifer Hydrick, Zigang Duan, Mark Greenberg, James Fiorenza, Lukas Chrostowski and Guangrui Xia,”Monolithic integration of AlGaAs distributed Bragg reflectors on virtual Ge substrates via aspect ratio trapping”, 5th international SiGe Technology and Device Meeting, May 2010.
- Tania Tasmin, Nicolas Rouger, Guangrui Xia, Lukas Chrostowski, Nicolas A.F. Jaeger,“Design of a 1550 nm SiGe/Si Quantum-Well Optical Modulator”, Photonics North Conference 2010, Niagara Falls, Ontario, Canada, 2010.
- B. Yang, R. Takalkar, Z. Ren, L. Black, A. Dube, J. W. Weijtmans, J. Li, J. B. Johnson, J. Faltermeier, A. Madan, Z. Zhu, A. Turansky, Guangrui Xia, A.Chakravarti, R.Pal, K.Chan, A.Reznicek, T.N.Adam, B.Yang, J.P.de Souza, E.C.T.Harley, B.Greene, A.Gehring, M.Cai, D.Aime, S.Sun, H.Meer, J.Holt, D. Theodore, S.Zollner, P.Grudowski, D.Sadana, D.-G.Park, D.Mocuta, D.Schepis, E.Maciejewski, S.Luning, J. Pellerin, and E.Leobandung, “High-performance nMOSFET with in-situ phosphorus-doped embedded Si:C (ISPD eSi:C) source-drain stressor”, Technical Digest – IEEE International Electron Devices Meeting(IEDM) 2008, pp. 51.
- Z. Ren, G. Pei, J. Li, F. Yang, R. Takalkar, K. Chan, Guangrui Xia, Z. Zhu, A. Madan, T. Pinto, T. Adam, J. Miller, A. Dube, L. Black, J. W. Weijtmans, B. Yang, E. Harley, A. Chakravarti, T. Kanarsky, I. Lauer, D.-G. Park, and D. Sadana, “On Implementation of Embedded Phosphorus-doped SiC Stressors in SOI nMOSFETs,” Tech. Dig. — IEEE Symp. on VLSI Tech. 2008, pp. 172.
- Judy L Hoyt, Cait Ni Chleirigh, Leonardo Gomez, Ingvar Aberg and Guangrui Xia,“Strained Si-Ge Heterostructure Channel Materials for Bulk and Ultra-thin Body MOSFETs,” Materials Research Society Symposium Proceedings, vol. 995E, April 2007.
- Guangrui Xia, Michael Canonico, and Judy L. Hoyt, “Interdiffusion in SiGe/Si Epitaxial Heterostructures,” 2006 International SiGe Technology and Device Meeting,May 2006, Princeton, NJ, USA, pp. 15B.4.
- Dalaver Anjum, Jian Li, Guangrui Xia, Judy L. Hoyt, and Robert Hull, “Characterization of ultrathin strained-Si channel layers of n-MOSFETs using transmission electron microscopy,” Materials Research Society Symposium Proceedings, vol. 864, E3. 9.1, Spring 2005. pp. 131-6
- Guangrui Xia, H. M. Nayfeh, M.-J. Lee, E.A. Fitzgerald, D.A. Antoniadis, J. Li, D.H. Anjum, R. Hull, and J.L. Hoyt, “Impact of Ion Implantation Damage and Thermal Budget on Mobility Enhancement in Strained Si n-MOSFETs,” 45th Electronic Materials Conference (EMC), Salt Lake City, Utah, June 25, 2003.
- J. L. Hoyt, H. M. Nayfeh, S. Eguchi, I. Aberg, Guangrui Xia, T. Drake, E. A. Fitzgerald, and D. A. Antoniadis, “Strained silicon MOSFET technology,” Technical Digest-International Electron Devices Meeting 2002, pp. 23-26.
- Guangrui (Maggie) Xia and Yuanwei Dong, “Si-Ge interdiffusion, dopant diffusion and segregation in SiGe and SiGe: C based devices”, Chapter 2 in the book of “Micro- and Nanoelectronics: Emerging Device Challenges and Solutions” edited by Tomasz Brozek, CRC Press 2015 Print ISBN: 978-1-4822-1490-1, eBook ISBN: 978-1-4822-1491-8We.
- Guangrui (Maggie) Xia and Yiheng Lin, “Base Doping Profile Engineering for High performance SiGe PNP Heterojunction Bipolar Transistors”, Chapter 4 in “High-Speed and Lower Power Technologies: Electronics & Photonics”, edited by Tomasz Brozek and Jung Han Choi, CRC Press, 2018, ISBN 9780815374411 – CAT# K338522.[Re
Xia Research Group website: https://mtrl-xia.sites.olt.ubc.ca/
High resolution confocal micro-Raman system in Dr. Xia’s lab (FF205)
- 325/442/633 nm polarized lasers
- Laser penetration depth in Si: 5 nm, 0.24 μm and >2 μm respectively
- High spectral resolution: 0.3 cm-1/pixel for 442 nm, 0.6 cm-1/pixel for 325 nm
- Resolution after peak fitting: 0.03 cm-1 for 442 nm, 0.06 cm-1 for 325 nm
- High spatial resolution: sub-μm laser spot size, 2D mapping capability
- Si stress measurement resolution: 15 MPa
- Ge concentration measurement resolution: 0.05% Ge
- Heating stage up to 1200°C, N2 or air ambient
- Heating rate up to 200°C/min
- Experience with Si, SiGe, Ge nanowires, III-V, carbon nanotubes, carbon fibers, graphene, Ti oxide, uranium oxide etc.
Microsystems and Nanotechnology Group (MiNa) at UBC: http://www.mina.ubc.ca/
UBC’s nanofabrication facility AMPEL: http://www.ampel.ubc.ca/
SiGe Research at Prof. D. J. Paul’s group at Glasgow University: http://userweb.eng.gla.ac.uk/douglas.paul/SiGe.html
TCAD and process physics research at University of Washington: http://www.ee.washington.edu/faculty/dunham/
Si and Ge based electronic-photonic device research at MIT: http://photonics.mit.edu/Research.html
Related materials from MIT OpenCourseWare: 6.774 Physics of Microfabrication: Front End Processing:
6.720 Integrated Microelectronic Devices: