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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1578-1581页

作者： lau keimay Photonics Technology Center Department of Electronic and Computer EngineeringHong Kong University of Science and Technology

AlGaN/GaN high electron mobility transistors(HEMTs) were grown on Si substrates by *** the HEMT structure,a 1 μm GaN buffer layer was partially doped with Mg in an attempt to increase the resistivity and minimize the buffer *** AlGaN/GaN HEMTs grown on undoped and partially Mg-doped GaN buffer layers were processed and the DC characteristics of the devices were characterized for comparing the effect of Mg *** the device with the partially Mg-doped GaN buffer layer,a lower drain leakage current density of 55.8 nA/mm,a lower gate leakage current density of 2.73 μA/mm,and a higher off-state breakdown voltage of 104 V were achieved with device dimensions Lg/Wg/Lgs/Lgd=1/10/1/1 μm,better than the device with the undoped GaN buffer layer,which has a higher drain leakage current density of 9.2 μA/mm,a higher gate leakage current density of 91.8 μA/mm,and a lower off-state breakdown voltage of 87 V with the same device dimensions.

关键词： AlGaN/GaN HEMT Si substrate MOCVD breakdown voltage Mg-doped

Improved GaN grown on Si(111) substrate using ammonia flow modulation on SiN_x mask layer by MOCVD

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Science China(Technological Sciences) 2009年第9期52卷 2758-2761页

作者： NG KaiWei lau keimay Department of Electrical and Electronic Engineering Hong Kong University of Science & Technology Clear Water BayKowloon Hong Kong China

In this paper,1 μm n-GaN was grown by using varied and fixed ammonia flow (NH3) on SiNx mask layer on Si(111) substrate using metal organic chemical vapor deposition (MOCVD). In-situ optical reflectivity traces of GaN growth show that the three-to two-dimensional process has been prolonged by using varied ammonia flow on SiNx mask layer method compared with that grown by fixing ammonia flow. Structural and optical properties were characterized by high-resolution X-ray diffraction and photolu-minescence,and compared with the sample grown by fixing ammonia flow,GaN grown using the varied ammonia flow on SiNx mask layer showed better structure and optical quality. It was assumed that the low NH3 flow in the initial growth stage considerably increased the GaN island density on the nano-porous SiNx layer by enhancing vertical growth. Lateral growth was significantly favored by high NH3 flow in the subsequent step. As a result,the improved crystal and optical quality was achieved utilizing NH3 flow modulation for GaN buffer growth on Si(111) substrate.

关键词： GaN epilayer MOCVD NH3 modulation

Metamorphic AlInAs/GaInAs HEMTs on silicon substrates by MOCVD

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Science China(Physics,Mechanics & Astronomy) 2011年第10期54卷 1815-1818页

作者： LI HaiOu HUANG Wei LI SiMin TANG ChakWah lau keimay Information and Communication College Guilin University of Electronic Technology Guilin 541004 China Department of Electronics and Computer Engineering Hong Kong University of Science and Technology 58th Research Institute China Electronics Technology Group Corporation Wuxi 214061 China

Metamorphic Al0.50In0.50As/Ga0.47In0.53As high electron mobility transistors (mHEMTs) grown by Metal Organic ChemicalVapor Deposition (MOCVD) on n-type silicon substrates with introduction of a novel multi-stage buffering stack scheme havebeen fabricated for the first time. 1.0- m-gate-length depletion-mode mHEMTs with maximum transconductance up to 613mS/mm are achieved. The unity current gain cut-off frequency (fT) and the maximum oscillation frequency (fmax) are 36.9 and55.6 GHz, respectively. This device has the highest fTyet reported for 1.0- m-gate-length HEMTs grown on silicon byMOCVD. Also, this performance is comparable to that of similar GaAs-based mHEMTs. These are encouraging initial resultsleading to the manufacturing potential of integrated high-speed metamorphic devices for logic applications on silicon sub-strates by MOCVD.

关键词： HEMT器件 MOCVD GaInAs 硅衬底变质高电子迁移率晶体管最高振荡频率金属有机

Fabrication of 0.3-m T-gate metamorphic AlInAs/GaInAs HEMTs on silicon substrates using metal organic chemical vapor deposition

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Science China(Physics,Mechanics & Astronomy) 2012年第4期55卷 644-648页

作者： TANG ChakWah lau keimay Department of Electronics and Computer Engineering Hong Kong University of Science and Technology

We present an InGaAs metamorphic high electron mobility transistor(mHEMT) grown using Metalorganic Chemical Vapor Deposition(MOCVD) on an n-type silicon substrate with the introduction of an effective multi-stage buffering *** and performance of a high-frequency 0.3-m gate-length depletion-mode Al 0.50 In 0.50 As/Ga 0.47 In 0.53 As mHEMT is reported for the first *** a combined optical and e-beam photolithography technology,submicron mHEMT devices on Si have been *** non-alloyed ohmic contact resistance R c was as low as 0.065-mm.A maximum transconductance up to 761 mS/mm was *** unity current gain cut-off frequency(fT) and the maximum oscillation frequency(fmax) were 72.8 and 74.5 GHz,*** device has the highest fT yet reported for a 0.3-m gate-length Si-based mHEMT grown using MOCVD.A high voltage gain,g m /g ds,of 40.6 is observed in the device.

关键词：化学气相沉积法 MHEMT 有机金属 gainas 硅衬底变质 MOCVD生长高电子迁移率晶体管