GaN . MOCVD. HEMTs nm μm GaN. AlGaN cm - 2. RIE Ti / Al / Ni / Au 22 nm /140 nm /55 nm / 40 s. Ni / Au / Ni 45 nm /200 nm /20

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1 Acta Phys Sin Vol 60 No * GaN GaN HEMTs GaN HEMTs GaN HEMTs PACS Ey Qv 1 field-plate GaN HEMTs HEMTs MOCVD nm AlN 1 4 μm GaN 1 5 nm AlN 23 nm AlGaN 2 nm GaN 5 8 AlGaN GaN HEMTs Al 30% Hall Ω / 1418 cm 2 / V s AlGaN GaN cm - 2 HEMTs RIE Ti / Al / Ni / Au 22 nm /140 nm /55 nm / nm s 16 Ni / Au / Ni 45 nm /200 nm /20 nm PECVD 60 nm SiN SiN Ti / Au 20 nm /100 GaN HEMTs nm PECVD 200 nm SiN Ti / Au 20 nm /100 nm * JY ZX mwxidian@ 126 com 2011 Chinese Physical Society http / / wulixb iphy ac cn

2 Acta Phys Sin Vol 60 No Keithley 4200-SCS gfp gsfp 0 6 μm μm 100 μm 500 ns 0 1 ms 0 4 μm 0 2 V DSQ = 15 V V DS = 10 μm 0 9 μm 1 V V GSQ = - 8 V V GS = V m V m V DS = 10 V V GS = V m 2 SiN 2 V 55% gfp 40% gsfp 33% 15% 22% 1 GaN HEMTs 3 V DS = 15 V gfp gsfp ma / mm ma / mm ma / mm 2 a b c

3 Acta Phys Sin Vol 60 No V DSQ = 15 V V GSQ = - 8 V 3 3 Silvaco atlas 1 Caughey Shockley - Read - Hall AlN AlN cm 2 / V s cm - 2 AlGaN GaN GaN AlGaN cm GaN cm ev cm 2 GaN cm ev cm 2 GaN GaN 4 GaN 1 6 μm 5 7 gsfp 9 2 gsfp SiN 160 nm 4 5 GaN

4 Acta Phys Sin Vol 60 No gfp 95% gsfp gfp gsfp gsfp 2 6 Simmons Taylor 22 F = pσ p v p + e n nσ n v n + pσ p v p + e n + e p e n = σ n n i v n exp E t - E i / kt e p = σ p n i v p exp E i - E t / kt n p n i σ n σ p v n v p E i E t k T n p 5 GaN GaN 7 GaN 5 gfp 7 gfp gsfp gsfp gsfp gsfp gsfp 7 GaN 6 7 GaN 6 gfp gsfp gsfp

5 Acta Phys Sin Vol 60 No gfp gsfp gfp gsfp SiN 7 GaN HEMTs Kumar V Chen G Guo S P Adesida I 2006 IEEE Transactions on Electron Devices Wu Y F Moore M Wisleder T Saxler A Parikh P 2006 IEEE 64th Device Research Conference PA USA June 2006 p151 3 Wei W Hao Y Feng Q Zhang J C Zhang J F 2008 Acta Phys Sin in Chinese Lee J W Kuliev A S Adesida I 2008 Japanese Journal of Applied Physics Koudymov A Adivarahan V Yang J Simin G Khan A A 2005 IEEE Electron Device Letters Wei W Lin R B Feng Q Hao Y 2008 Acta Phys Sin in Chinese Nakajima A Itagaki K Horio K 2009 Phys Status Solidi Brannick A Zakhleniuk N A Ridley B K Shealy J R Schaff W J Eastman L F 2009 IEEE Electron Device Letters Daumiller I Theron D Gaquiere C Vescan A Dietrich R Wieszt A Leier H Vetury R Mishra U K Smorchkova I P Nguyen N X Kohn E 2001 IEEE Electron Device Letters Xi G Y Ren F Hao Z B Wang L Li H T Jiang Y Zhao W Han Y J Luo Y 2008 Acta Phys Sin in Chinese Tirado J M Sanchez-Rojas J L Izpura J I 2007 IEEE Transactions on Electron Devices Meneghesso G Rampazzo F Kordos P Verzellesi G Zanoni E 2006 IEEE Transactions on Electron Devices Romero M F Jimenez A Sanchez J M Brana A F Gonzalez - Posada F Cuerdo R Calle F Munoz E 2008 IEEE Electron Device Letters Yang L Hao Y Ma X H Quan S Hu G Z Jiang S G Yang L Y 2009 Chin Phys Lett Hu G Z Yang L Yang L Y Quan S Jiang S G Ma J G Ma X H Hao Y 2010 Chin Phys Lett Shen L Palacios T Coblenz C Corrion A Chakraborty A Fichtenbaum N Keller S Denbaars S P Speck J S Mishra U K 2006 IEEE Electron Device Letters Zhou Z T Guo L W Xing Z G Ding G J Tan C L Lu L Liu J Liu X Y Jia H Q Chen H Zhou J M 2007 Acta Phys Sin in Chinese Ambacher O Smart J Shealy J R Weimann N G Chu K Murphy M Schaff W J Eastman L F 1999 Journal of Applied Physics Piprek J 2007 Nitride Semiconductor Devices - Principles and Simulation New York Wiley-VCH p Faqir M Verzellesi G Chini A Fantini F Danesin F Meneghesso G Zanoni E Dua C 2008 IEEE Transactions on

6 Acta Phys Sin Vol 60 No Device and Materials Reliability Vetury R Zhang N Q Keller S Mishra U K 2001 IEEE Transactions on Electron Devices Simmons J G Taylor G W 1971 Phys Rev B Study on the suppression mechanism of current collapse with field-plates in GaN high-electron mobility transistors * Mao Wei Yang Cui 2 Hao Yue Zhang Jin-Cheng Liu Hong-Xia Ma Xiao-Hua 2 Wang Chong Zhang Jin-Feng Yang Lin-An Xu Sheng-Rui Bi Zhi-Wei Zhou Zhou Yang Ling Wang Hao School of Microelectronics Xidian University Key Lab of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices Xi an China 2 School of Technical Physics Xidian University Xi an China Received 3 July 2010 revised manuscript received 10 August 2010 Abstract The physical mechanisms underlying current collapse effects in the passivated GaN high-electron mobility transistors HEMTs the gate field-plated GaN HEMTs and the gate-source field-plated GaN HEMTs are investigated in experiments and numerical device simulations And the intrinsic relationships of the current collapse with the carrier concentration the probability of traps ionization and the electric field within the cap layer are established Results show that the direction of the longitudinal electric field as well as the intensity distribution of both the transverse and longitudinal electric fields within the cap layer can be modulated effectively by the field-plates The electric field intensity near the gate is reduced and that beneath the field-plates increased Due to the effects of the field-plates on electric field the transverse movement of electrons near the gate is reduced and the longitudinal electron movement beneath the field-plates is increased These affects the electron concentration distribution and the ionization probability of the traps in the cap layer which makes field-plates effective for the reduction in the current collapse Keywords current collapse passivated devices field-plated devices probability of traps ionization PACS Ey Qv * Project supported by the Fundamental Research Funds for the Central Universities Grant No JY the National Natural Science Foundation of China Grant Nos and the National Key Science & Technology Special Project Grant No 2008ZX mwxidian@ 126 com