Prof. Kei May Lau
Hong Kong University of Science and Technology

III-V compounds have established their niches in optoelectronic, high- frequency and high-speed device applications that cannot be matched by Si electronics. However, Si has been and will remain the workhorse in the semiconductor industry. To further improve the performance and extend the functionalities of Si-based electronics, the best approach is to combine these well-developed materials and related technologies. Our group has been investigating integration of III-V devices on a Si platform. Using metamorphic growth of III-V materials, high quality devices can be directly grown and fabricated on Si substrates that will allow continued use of the traditional and ever improving manufacturing technologies for Si.

In this talk, I will discuss various hetero-epitaxy techniques, including III-Nitrides growth on Si and metamorphic devices (lattice- matched to InP) on GaAs/Si substrates. The former allows the use of low cost and large size Si substrates for manufacture of LEDs and high- temperature electronics. InP-based HEMTs and HBTs are high- performance devices normally grown on high-cost and fragile InP substrates. Our group first reported metamorphic devices on GaAs by MOCVD with excellent RF performance. We then used similar techniques putting these high-speed devices on Si substrates for digital applications. Various metamorphic growth issues pertinent to device performance and manufacturability will be addressed. Strain management and cracking are major concerns, as well as high resistivity buffers for minimizing device leakage and defect reduction. Preliminary device results such as mHEMTs on Si will be reported. Al0.50In0.50As/Ga0.47In0.53As mHEMT structures grown on silicon substrates exhibited 2-DEG mobilities > 6000 cm2/V-s and sheet carrier densities > 6 x 10^12 cm-2 at room temperature. 1-µm gated transistors with Gm > 600mS/mm demonstrated fmax up to 50GHz.

Professor Kei May Lau received the B.S. and M.S. degrees in physics from the University of Minnesota, Minneapolis, and the Ph.D. degree in Electrical Engineering from Rice University, Houston, Texas. She worked on epitaxial growth of GaAs for microwave devices at M/A-COM Gallium Arsenide Products, Inc. for two years, before joining the faculty of Electrical and Computer Engineering Department at the University of Massachusetts/Amherst. Prof. Lau initiated MOCVD, compound semiconductor materials and devices programs at UMass. Her research group conducted research on heterostructures, quantum wells, strained-layers, III-V selective epitaxy, high frequency and photonic devices. Professor Lau spent her first sabbatical leave in 1989 at the MIT Lincoln Laboratory and worked with the Electro-optical Devices Group. She developed acoustic sensors at the DuPont Central Research and Development Laboratory in Wilmington, Delaware during her second sabbatical leave ('95-'96). Since the fall of 2000, she has been with the Electronic and Computer Engineering Department at the Hong Kong University of Science and Technology (HKUST). She established the Photonics Technology Center for R&D effort in III-V materials, optoelectronic, high power, and high-speed devices. Professor Lau is a Fellow of the IEEE, and a recipient of the National Science Foundation (NSF) Faculty Awards for Women (FAW) Scientists and Engineers (1995) and Croucher Senior Research Fellowship (2008). She served on the IEEE Electron Devices Society Administrative Committee and was an Editor of the IEEE Transactions on Electron Devices (1996-2002). She also serves on the Electronic Materials Committee of the Minerals, Metals and Materials Society (TMS) of AIME (American Institute of Materials Engineers), and was an Editor of the Journal of Crystal Growth.