在本文中，成功研製了新式In0.2Ga0.8AsSb/GaAs摻雜式通道場效應電晶體，Sb在成長InGaAsN/GaAs量子井時，可當成一種類似活化劑的作用，其優點是可以抑制三維表面成長，阻止島狀形成更進一步減小能隙，使的改善量子井各層薄膜之間的界面品質。
實驗結果顯示，InGaAsSb/GaAs DCFET的通道界面品質，藉由加入類似表面活化劑微量元素Sb可以有效改善成長品質及元件的特性，包括最大轉導值 135.5 ms/mm，最大飽和電流 248 mA/mm，閘極電壓擺幅 1.25 V，截止頻率和最大震盪頻率分別為12 GHz和18 GHz，也顯示出穩定熱臨界電壓變化率 -0.47 mV/K，元件閘極長度1.2 μm，閘極寬度200 μm。
為了更進一步改善元件特性，我們使用5％(NH4)2Sx溶液來改善蕭基接面。在蕭基接面存在著大量的懸鍵導致產生陷阱，造成元件特性的衰退。經由硫化處理後，硫原子可以跟GaAs表面懸鍵形成安定鍵結及較佳平坦度，所以可以減少表面的陷阱，形成一個較好的蕭基接面。從實驗結果知，IDSS0從176 mA/mm 增加至187 mA/mm；Gm(max)從135.5 mS/mm 增加至166 mS/mm，VGD：-14.6 V增加至 -16 V，也進一步改善功率特性，使得輸出功率由 9.91 dBm 增加至12.11 dBm。由實驗結果知，利用硫化處理可以得到元件最佳特性。

This work reports for a novel In0.2Ga0.8AsSb/GaAs heterostructure doped-channel field-effect transistor (DCFET) grown by the molecular beam epitaxy system. The advantages by incorporating the surfactant-like Sb atoms during growth of InGaAsN/GaAs quantum well (QW) consist of the suppression of the three-dimensional growth and reduced slightly band gap. Then, it improved interfacial quality of QW heterostructure.
The interfacial quality within the InGaAsSb/GaAs quantum well of the DCFET device has effectively improved by introducing surfactant-like Sb atoms during the growth of the Si-doped InGaAs Channel layer. The improved device characteristics include the peak extrinsic transconductance of 135.5 mS/mm, the peak drain-source saturation current density of 248 mA/mm, the gate-voltage swing of 1.25 V, the cutoff frequency of 12 GHz and the maximum oscillation frequency 18 GHz at the gate dimensions of 1.2×200 μm2 .The proposed design has also shown a stable thermal threshold coefficient of -0.47 mV/K.
In order to improve device characteristics even, we use 5% (NH4)2Sx solutions to improve Schottky interface. The Schottky interface exists a lot of dangling bonds which generate traps and result in device degeneration. By (NH4)2Sx treatment, Sulfur atoms can form static bonds with dangling bonds of GaAs surface and get better roughness. Then, it results that the gate control ability is better. From the experimental results, the peak saturated drain-source current density could be from 248 mA/mm to 268 mA/mm. The maximum extrinsic transcondictance could be from 135.5 mS/mm to 166 mS/mm. The breakdown voltage and could be from -14.6 V to -16 V. Then, it can further improve high power characteristics. The out power is from 9.91 dBm to 12.11 dBm. From the experimental results, devices get better characteristics by (NH4)2Sx treatment.

【1】 Y W Chen, W C Hsu, R T Hsu, and Y H Wu, and Y J Chen, “Characteristics of In0.52Al0.48As/InxGa1−xAs HEMT’s with various InxGa1−xAs channels” Solid State Electron 48 p. 119 ,2004
【2】 P H Lai, C W Chen, C I Kao, S I Fu, Y Y Tsai, C W Hung, C H Yen, H M Chuang, S Y Cheng, and W C Liu “Influences of sulfur passivation on temperature-dependent characteristics of an AlGaAs/InGaAs/GaAs PHEMT”, IEEE Trans. Electron Devices 53 p. 1 , 2006
【3】 G. Meneghesso, A. Neviani, R. Oesterholt, M. Matloubian, T. Liu, J. J. Brown, C. Canali, and E. Zanoni, “On-state and off-state breakdown in GaInAs/InP composite-channel HEMT's with variable GaInAs channel thickness”,IEEE Electron Device 46 p. 2 ,1999
【4】 W S Lour, M K Tsai, K C Chen, Y W Wu, S W Tan, and Y J Yang, “Dual-gate In0.5Ga0.5P/In0.2Ga0.8As pseudomorphic high electron mobility transistors with high linearity and variable gate-voltage swing” Semicond.r Sci. Techno. 16 p. 826 ,2001
【5】 W C Hsu, Y J Chen, Lee C S, T B Wang, J C Huang, D H Huang, K H Su, Y S Lin, and C L Wu, “Characteristics of In0.425Al0.575As/InxGa1-xAs Metamorphic HEMTs with Pseudomorphic and Symmetrically-Graded Channels,” IEEE Electron Device 52 p. 1079 , 2005
【6】 J H Tsai, “A novel InGaP/InGaAs/GaAs double /spl delta/-doped pHEMT with camel-like gate structure” IEEE Electron Device Lett. 24 p. 1 , 2003

【7】H M Chung, S Y Cheng, C Y Chen, X D Liao, R C Liu, and W C Liu, “Investigation of a New InGaP/InGaAs Pseudomorphic Double Doped-Channel Heterostructure Field-effect Transistor (PDDCHFET)” IEEE Electron Device 50 p. 1717 ,2003
【8】 P. H. Lai, R. C. Liu, Ssu-I Fu, Y. Y. Tsai, C. W. Hung, T. P. Chen, and W. C. Liu“Effect of Formal Passivation on Temperature-Dependent Characteristics of High Electron Mobility Transistors” Journal of The Electrochemical Society ,2007.
【9】 P. H. Lai, R. C. Liu, Ssu-I Fu, Y. Y. Tsai, C. W. Hung, T. P. Chen, and W. C. Liu
“Influences of Sulfur Passivation on Temperature-Dependent Characteristics of an AlGaAs/InGaAs/GaAs PHEMT ”IEEE Trans. Electron Devices vol. 53, NO.1 , 2006.
【10】 H. C. Chiu, Y.C. Hung, C. W. Chen, L. B. Chang,“Electrical Characteristics of Passivated Pseudomorphic HEMTs with P2S5/(NH4)2SX Pretreatment”IEEE Trans. Electron Devices vol. 55, NO.3 ,2008.
【11】B. Kim, R. J. Matyi, M. Wurtele, K. Bradshaw, M. A. Khatibazadeh, and H. Q. Tserng,“Millmeter-wave power operation of an AlGaAs/InGaAs/GaAs quantum well MISFET,”IEEE Trans. Electron Device, vol. 36, p. 2336, 1989
【12】P. P. Reden, M. Shur, A.I.Akinwande, D. E. Grider, and J. Beak, “AlGaAs/InGaAs/GaAS quantum well doped channel heterostructure field effect transistors,”IEEE Trans. Electron Device, vol. 37, p. 2171, 1990.
【13】Y. J. Chan, M. T. Yang, T. J. Yeh, and J. I. Chyi,“High uniformity of AlGaAs/In0.15Ga0.85As doped-channel structure grown by MBE on 3 GaAs subtrates,”J. Electronic MATERIALS, vol. 23, p. 675, 1994.
【14】S. R. Bank, H. W. Gambin, V. Wistey, M.A. Yuen, H. B. Goddard, L. L.Kim, S. M. Harris, J. S. Jr.“1.5 mm InGaAsNSb lasers grown on GaAs by MBE,”J. Cryst. Growth, vol.251, p. 367, 2003.
【15】 K. H. Su, W. C. Hsu, C. S. Lee, T. Y. Wu, Y. H. Wu, L. Chang, R. S. Hsiao, J. F. Chen and T. W. Chia, “Novel Dilute Antimony Channel In0.2Ga0.8AsSb/GaAs HEMT,” IEEE Electron Device Lett, vol. 28, p. 91, 2007.
【16】 A. Hasse, K. Volz, A. K. Schaper, J. Koch, F. Ho¨hnsdorf and W. Stolz, “TEM Investigations of (GaIn)(NAs)/GaAs multi-quantum wells grown by MOVPE”, Cryst. Res. Technol., vol. 35, p. 787, 2000
【17】C. C. Chang, C. H. Chien, G. L. Luo, C. K. Tseng, H. C. Chiang, C. H. Yang, and C. Y. Chang“Improved Electrical Properties of Gd2O3/GaAs Capacitor with Modified Wet-Chemical Clean and Sulfidization Procedures”Journal of The Electrochemical Society , 2008.
【18】H. C. Chiu, Y.C. Hung, C. W. Chen, L. B. Chang,“Electrical Characteristics of Passivated Pseudomorphic HEMTs with P2S5/(NH4)2SX Pretreatment” IEEE Trans. Electron Devices vol.55, NO.3 ,2008.
【19】C. T. Lee, M. H. Lan,and C. D. Tasi,“Improved performances of InGaP Schottky contact with Ti/Pt/Au metals and ssm photodetectors by (NH4)2Sx treatment”, Solid State Electron, vol. 41 , pp.1715-1719, 1997
【20】S. M. Sze, Semiconductor Devices Physics and Technology, New York: Wiley, p.48, 2002.
【21】Willian Liu, Handbook of III-V Heterojunction Bipolar Transistor, New York: Wiely,p. 103, 1998.
【22】Hideaki lkoma, Kenji Sato, and Toshiki lshida, “Current-voltage characteristics and interface state density of GaAs Schottky barrier” Appl. Phys. Lett. 62, p. 2560, 1993.
【23】H. Sik, Y. Feurprier, C. Cardinaud, G. Turban, and A. Scavenenc“Reduction of Recombination Velocity on GaAs Surface by Ga-S and As-S Bond-Related Surface State from (NH4)2Sx Treatment”Journal of The Electrochemical Society, vol. 144, No. 6, 1997.
【24】Y. K. Kim, S. Kim, J. M. Seo, S. Ahn, K. J. Kim, T. K. Kang, and B. Kim, “Metal-dependent Fermi-level movement in the metal/sulfur-passivated InGaP contact”, Journal of The Electrochemical Society, vol. 82, pp.4076-4080, 1997.
【25】P. G. Young, S. A. Alterovitz, R. A. Mena and E. D. Smith, “RF Properties of Epitaxial Lift-Off HEMT Devices” IEEE trans. electron devices., vol. 40, p. 1905, 1993.
【26】K. Kiziloglu, H. Ming, D. S. Harvey, R. D. Widman, C. E. Hooper, P. B. Janke, J. J. Brown, L. D. Nguyen, D. P. Docter and S. R. Burkhart, “High-performance AlGaAs/InGaAs/GaAs PHEMTs for K and Ka-band applications,” Microwave Symposium Digest, IEEE MTT-S International, vol. 2, p. 13, 1999.
【27】M. Miyashita, N. Yoshida, Y. Kojima, T. Kitano, N. Higashisaka, J. Nakagawa, T. Takagi and M. Otsubo, “An AlGaAs/InGaAs pseudomorphic HEMT modulator driver IC with low power dissipation for 10-Gb/s optical transmission systems”, Microwave Theory and Techniques, vol. 45, p. 1058 ,1997.
【28】P. Cova, R. Menozzi, D. Lacey, Y. Baeyens and F. Fantini, “High performance electron devices for microwave and optoelectronic applications,” EDMO., IEEE 1995 Workshop, 1995.
【29】R. Menozzi, M. Borgarino, Y. Baeyens, M. Van Hove and F. Fantini, “On the effects of hot electrons on the DC and RF characteristics of lattice-matched InAlAs/InGaAs/InP HEMTs,” IEEE Microwave and Guided Wave Lett., vol. 7, p. 3, 1997.

【30】Y. K. Fang, C. M. Lai, Y. T. Chiang,“Evaluation of post-annealing-induced defects dynamic behaviors on 90 nm In-halo nMOSFETs with low frequency noise and charge pumping measuring techniques”IEEE Electron. Device Letters vol. 28, p.142-4, 2007.