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研究生： 葉炅翰
Yeh, Jung-Han
論文名稱： Gamma形閘極異質結構電晶體之研究
Г-shape gate of Metamorphic Heterostructure Field Effect Transistor
指導教授： 許渭州
Hsu, Wei-Chou
學位類別： 碩士
Master
系所名稱： 電機資訊學院 - 微電子工程研究所
Institute of Microelectronics
論文出版年： 2007
畢業學年度： 95
語文別： 英文
論文頁數： 64
中文關鍵詞： 位移曝光技術 、異質結構電晶體 、鈍化層
外文關鍵詞： shift expose method, passivation, HFET
相關次數： 點閱：69  下載：2 
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    • 在本文中，我們以「分子束磊晶法」成功研製了以雙δ-摻雜為通道之異質結構場效電晶體，此外我們利用PECVD在蕭基層上成長了鈍化層，並進一步探討鈍化層對元件特性的影響，並利用＂位移曝光技術＂來建立並獲得次微米閘極結構(閘極尺寸0.5μm)。
    首先我們探討以In0.5Ga0.5As/δ+/In0.5Ga0.5As/In0.6Ga0.4As/In0.5Ga0.5As/δ+/In0.5 Ga0.5As為通道的異質結構場效電晶體，實驗結果指出由於此異質結構電晶體具有良好的載子侷限能力能將載子侷限在未摻雜的高銦含量通道中，使得此異質結構電晶體擁有高電子移動率和高載子濃度，獲得較好的直流(IDSS=482mA/mm)和微波特性(Pout=15.42dBm)。
    其次，我們在蕭基層上成長了鈍化層，在成長鈍化層前，我們利用了ISE-TCAD
    探討鈍化層厚度和崩潰電壓間的關係，並模擬加上鈍化層後在元件內部電場的分佈，實驗結果顯示，元件成長鈍化層後，在改善了表面缺陷的同時改變了蕭基特能障，縮小空乏區深度，提升了有效通道寬度，使得片載子濃度提高，提升了直流特性(IDSS=402mA/mm -> 422mA/mm)，同時因為電場散佈使得通道中最大電場減小，進而降低了衝擊離子化效應，除此之外，因為加上鈍化層使得電場線加長，進而改善了電流擁擠，使得崩潰電壓變大(VGD= 7.8V -> 9.8V)。
    最後，我們使用了＂ 位移曝光技術＂來縮小閘極長度，利用此一可靠且經濟的方法，我們成功製造了次微米閘極電晶體，進而改善元件微波特性(Ft=32.7GHz，Pout=16.73dBm)。

    In this work, we proposed a metamorphic heterostructure field-effect transistor with double δ-doped channel (MDDFET). In addition, We deposited a passivation(Si3N4) by PECVD on schottky layer. Finally we used “Shift expose method” to fabricate and obtain submicron gate structure. (gate length=0.5μm)
    First, we demonstrated a metamorphic heterostructure field-effect transistor with double δ-doped channel (MDDFET). The coupled δ-doped
    In0.5Ga0.5As/δ+/In0.5Ga0.5As/In0.6Ga0.4As/In0.5Ga0.5As/δ+/In0.5Ga0.5As channel demonstrates high carrier concentration and high mobility due to the good carrier confinement of the δ-doped design and the coupled wave function in the undoped In-rich channel. Experimental results indicate that the MDDFET with the gate dimension of 1 × 100 μm2 exhibits a maximum extrinsic transconductance of 234 mS/mm, a saturated drain-current density of 402 mA/mm at VGS = 0 V, a cut-off frequency of 20.8 GHz, a maximum oscillation frequency of 43 GHz, and a saturated power of 15.42 dBm at 2.4 GHz. These results demonstrate that this studied device is appropriate for high-current and high-power applications.
    Second, we deposited a passivation (Si3N4) by PECVD on schottky layer. Before we deposited passivation (Si3N4), we used ISE-TCAD to simulation the electrical field about MDDFET with passivation and gamma gate of MDDFET. Meanwhile, we probed into passivation thickness and breakdown voltage relationship. The passivation improved gate leakage current, surface trap, changed surface potential and sheet carrier concentration, so the DC characteristics were enhanced. Meanwhile, the electrics field spread made the maximum electrics field decrease, so the kink effects became insignificant. Furthermore, passivation can modify the electric field line which decreased field crowding effect and enhanced the breakdown voltage. Experimental results indicate that the passivated MDDFET with the gate dimension of
    1 × 100 μm2 exhibits a maximum extrinsic transconductance of 244 mS/mm, a saturated drain-current density of 422 mA/mm at VGS = 0 V, a cut-off frequency of 23 GHz, a maximum oscillation frequency of 45 GHz, and a output power of 16.07 dBm at 2.4 GHz.
    Finally, we used “shift expose method” to shrink gate length. By using this low cost and reliable method, we fabricated submicron gate transistor successfully and then improved the microwave characteristics in this device. Experimental results indicate that the gamma gate of MDDFET with the gate dimension of 0.5 × 100 μm2 exhibits a maximum extrinsic transconductance of 274 mS/mm, a saturated drain-current density of 323 mA/mm at VGS = 0 V, a cut-off frequency of 32.7 GHz, a maximum oscillation frequency of 89.7 GHz, and a saturated power of 16.73 dBm at 2.4 GHz.

    Contents Abstract (Chinese) Abstract (English) Figure Caption Chapter 1 1 Introduction 1 Chapter 2 4 Growth and Fabrication 4 2-1 Doped channel HFET Layer Design 5 2-1-1 Cap Layer 5 2-1-2 Schottky Layer 6 2-1-3 -doped Layer 6 2-1-4 InGaAs Channel Layer 7 2-1-5 Buffer Layer 8 2-1-6 Passivation Layer 8 2-2 Two-Dimensional Electron Gas 8 2-3 Device Fabrication Process 10 2-3-1 Sample Orienting 11 2-3-2 Source and Drain Metallization 11 2-3-3 Mesa Isolation 12 2-3-4 Gate Schottky Contact 12 2-3-5 Gamma Gate Schottky Contact 13 Chapter 3 14 Results and Discussions 14 3-1 Device Structure 14 3-2 Device simulation result 14 3-3 Hall Measurement 15 3-4 DC and RF Characteristics 16 3-4-1 Current-Voltage Characteristics 16 3-4-2 Extrinsic Transconductance and Saturation Current Density 17 3-4-3 Breakdown Voltage 18 3-4-4 Microwave Characteristics 19 3-4-5 Power Characteristic 21 Chapter 4 23 Conclusion 23 Figure Caption Fig. 2-1 Schematics cross section of a traditional HEMT structure Fig. 2-2 Bandgap versus lattice constant of Ⅲ-Ⅵ compound Fig. 2-3 Crystal arrangement of pseudomorphic HEMT structure Fig. 2-4 Critical layer thickness of InxGa1-xAs as a function of InAl mole fraction. Fig. 2-5 Self-consistent conduction band and 2DEG distribution Fig. 2-6 Flow chart of device fabrication process. Fig. 2-7 Flow chart of Г-gate fabrication process. Fig. 2-8 The SEM picture for gamma-shape gate MDDFET. Fig. 3-1 Schematic cross section of MDDFET Fig. 3-2 Gate leakage current of various HFETs. Fig. 3-3(a) Electrical field distribution of HFET without passivation. Fig. 3-3(b) Electrical field distribution of HFET with passivation. Fig. 3-3(c) Electrical field distribution of Г-gate HFET Fig. 3-4 Longitudinal electric fields within various HFETs InAlAs Schottky layer. Fig. 3-5 Gate leakage current with different passivation thickness. Fig. 3-6 Mobility and sheet electron density with different passivation thickness. Fig. 3-7 Energy band diagram of MDDFET before and after passivation. Fig. 3-8 Current-Voltage characteristic of MDDFET at room temperature. Fig. 3-9 Current-voltage characteristic before and after passivation of MDDFET. Fig. 3-10 Current-voltage characteristic of Г-gate MDDFET . Fig. 3-11 Extrinsic transconductance and saturation drain density current of MDDFET. Fig. 3-12 Extrinsic transconductance and saturation drain density current before and after passivation. Fig. 3-13 Extrinsic transconductance and saturation drain density current Fig. 3-14 Two terminal gate-to-drain breakdown voltage. Fig. 3-15 Two terminal gate-to-drain breakdown voltage before and after passavated MDDFET. Fig. 3-16 Two terminal gate-to-drain breakdown voltage of gamma-gate MDDFET. Fig. 3-17 Microwave characteristics of MDDFET. Fig. 3-18 Microwave characteristics versus VGS of MDDFET. Fig. 3-19 Microwave characteristics of passivated MDDFET. Fig. 3-20 Microwave characteristics of gamma-gate MDDFET. Fig. 3-21 Power characteristic of MDDFET. Fig. 3-22 Power characteristic of passivated MDDFET. Fig. 3-23 Power characteristic of gamma-gate MDDFET.

    References

    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. H M Chuang, S Y Cheng, P H Lai, X D Liao, C Y Chen, C H Yan, R C Liu, and W C Liu, “Study of InGaP/InGaAs double doped channel heterostructure field-effect transistors (DDCHFETs)” Semicond. Sci. Techno. 19 p. 87 , 2004
    9. H. R. Chen, M. K. Hsu, S. Y. Chiu,W. T. Chen, G. H. Chen, Y. C. Chang, and W. S. Lour, Member, IEEE, “InGaP/InGaAs Pseudomorphic Heterodoped ChannelFETs With a Field Plate and a Reduced Gate Length by Splitting Gate Metal”, IEEE Electron Device Lett, 27 p. 12 , 2006
    10. G,M. Metze, senior member, IEEE, J. F. Bass, T. T. Lee, Member, IEEE “A Dielectric-Defined Process for the Formation of T-Gate Field-Effect Transistors”, IEEE microwave and guided wave letters, 1 p. 3 1991
    11. K. S. Lee, Y. S. Kim, K. T. Lee, and Y. H. Jeong “Process for 20 nm T gate on Al0.25Ga0.75As/ In0.2Ga0.8As/GaAs epilayer using two-step lithography and zigzag foot” , JVST B 24, p. 4 2006
    12. Kamal Tabatabaie-Alavi, Senior Member, IEEE, Dale M. Shaw, and Paul J. “DuvalEvolution of T-Shaped Gate Lithography for Compound Semiconductors Field-Effect Transistors. “IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING, VOL. 16, NO. 3, p. 365 AUGUST 2003
    13. Naoki Hara, Member, IEEE, Kozo Makiyama, Tsuyoshi Takahashi, Ken Sawada, Tomoyuki Arai, Toshihiro Ohki,Mizuhisa Nihei, Toshihide Suzuki, Yasuhiro Nakasha, and Masahiro Nishi, “Highly Uniform InAlAs–InGaAs HEMT Technology for High-Speed Optical Communication System ICs”
    IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING, VOL. 16, NO. 3, p. 370 AUGUST 2003
    14. Woo-Suk SUL, Sam-Dong KIM_, Hyung-Moo PARK and Jin-Koo RHEE “Electrical Characteristics of the 0.1_m Gate Length Pseudomorphic High-Electron-MobilityTransistors with Low-Dielectric-Constant Benzo-Cyclo-Butene Passivations” Jpn. J. Appl. Phys. Vol. 42 p. 7189
    2003
    15. B. Vinter, “Subband and Charge Control in a Two-Dimensional Electron Gas Field-Effect Transistor,” Appl. Phys. Lett., vol. 44, p. 307, 1984.
    16. Karmalkar and G. Ramesh, “A Simple Yet Comprehensive Unified Physical Model of the 2D Electron Gas in Delta-Doped and Uniformly Doped High Electron Mobility Transistors,” IEEE Trans. Electron Devices, vol. 47, p.11, 2000.
    17. Y. Ando and T. Itoh, “Accurate Modeling for Parasitic Source Resistance in Two-Dimensional Electron Gas Field-Effect Transistors,” IEEE Trans. Electron Devices, vol. 36, p. 1036, 1989.
    18. F. Ali and A. Gupta, “HEMTs and HBTs : Devices, Fabrication, and Circuits, Norwood: Artech House”, p. 81, 1991.
    19. Y S Lin and Y L Hsieh “Investigation of the Luminescent Properties of Tb3+-Substituted YAG:Ce, Gd Phosphors” J. Electrochem. Soc., p. 152, 2003
    20. C C Eugster, Tom P. E. Broekaert, J A Del Alamo, and Clifton “An InAlAs/InAs MODFET “IEEE Electron Device lett. 12 p. 707 1991
    21. A. Belache, A. Vanoverschelde, G. Salmer and M. Wolny, “Experimental analysis of HEMT behavior under low-temperature conditions,” IEEE Trans. Electron Devices, vol. 38, p. 3, 1991.
    22. E. Skuras, C. R. Stanleya, “Fermi energy pinning at the surface of high mobilityIn0.53Ga0.47As/ In0.52Al0.48As modulation doped field effect transistor Structures” APPLIED PHYSICS LETTERS 90 ,p. 133506 2007
    23. Masataka Higashiwaki,a_ Norio Onojima, and Toshiaki Matsui , Takashi Mimura, “Effects of SiN passivation by catalytic chemical vapor deposition
    on electrical properties of AlGaN/GaN heterostructure field-effect transistors” JOURNAL OF APPLIED PHYSICS 100, p. 033714 2006
    24. Y J Chen, W C Hsu, Y W Chen, Y S Lin, R T Hsu, and Y H Wu, “InAlAs/InGaAs doped channel heterostructure for high-linearity, high-temperature and high-breakdown operations.” Solid State Electron 49 p. 163 2005
    25. P.G. Young, S.A. Alterovitz, R.A. Mena and E.D. Smith, “RF Properties of Epitaxial Lift-Off HEMT Devices” IEEE Transactions on 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.

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