臺灣博碩士論文加值系統

中文摘要
由於砷化鋁鎵/砷化鎵異質接面雙載子電晶體具有優異的電流增益、操作速度以及其低電壓動作等特性，因此特別適合應用於微波、高功率及低電壓的操作系統，但是由於砷化鋁鎵/砷化鎵異質接面雙載子電晶體常應用於高功率密度環境及本身砷化鎵材料之低熱導係數影響，使得元件操作時外界與元件自身所產生的熱無法完全經由基板散逸至外界，使得元件之特性衰退；加上該材料的高表面複合速率(約106 cm/s)卻也導致漏電流過大，並直接降低其電流增益，因此探討元件之熱效應問題以及藉由一表面披覆處理以降低元件的表面複合，是迫切需要解決的問題。
我們成功地製作了砷化鋁鎵/砷化鎵異質接面雙載子電晶體，其中射極、基極及集極歐姆接觸電阻均可以達到10-6 W-cm2，而電流增益則可以達到100以上；並發現其熱效應問題，而砷化鋁鎵/砷化鎵異質接面雙載子電晶體在經過硫化處理後，我們利用光學顯微鏡、電子顯微鏡、原子力顯微鏡、X光頻譜分析儀及歐傑頻譜分析儀等設備，分析其表面與材料特性的變化，並利用半導體參數分析儀與網路分析儀等設備分析元件之直流與射頻特性。最後我們發現，在物性分析方面硫化處理改善砷化鎵表面狀況，並證明硫化效應是一擴散效應，隨硫化時間增加而擴散至更深處，而在電性方面，硫化處理過後之電晶體因散熱面積部份減少故其溫度影響電晶體導致電流衰退的效應更加的明顯，且射極面積也影響了散熱效率，射極面積大的散熱較快，較射極面積小的不易累積熱量於電晶體中，另一方面，硫化效應可以改善砷化鋁鎵/砷化鎵異質接面雙載子電晶體之直流特性，然而因基極電阻增加而其交流特性卻也因此劣化。

Abstract
Because of the high-current gain, operation speed, and low switch on voltage of the AlGaAs/GaAs Heterojunction Bipolar Transistors (HBTs), especially to applicate in microwave, high power, and low bias systems, but many applications will require HBTs to operate in high power density environments, the device performances were decaded because of the heat which created by itself and extrinsic environments that the heat can not dissipated to air from substrate due to the low thermal conductivity of the GaAs materials; except to the effect of thermal, the weakness of the AlGaAs/GaAs HBTs is the high surface recombination velocity (about 106 cm/s) that before the oxide layer deposited.
In the thesis, an AlGaAs/GaAs HBT was fabricated; the Emitter, Collector and Base characteristic resistances could be 10-6 W-cm2, and the current gain b can to 100. To observe the surface state with optic-microscopy, SEM, and AFM, the surface state has became better after ammonium sulfide treated; analysis the surface components with XPS and the diffusion effect was proved by AES; the thermal effect was discussed, the current and current gain were decaded because the sulfide layer reduce the heat dissipated to air.
The DC performance was improved by ammonium sulfide treated because of the surface passivation effect, however the RF performances were reduced, because of the sulfide effect is a diffusion effect and increased the base resistance.

中文摘要 i
Abstract ii
Figure indexI
Table indexVIII
概述 1
第一章 簡介1
第二章 背景理論2
第三章 實驗步驟3
第四章 結果與討論4
第五章 結論5
第六章 未來目標6
Chapter 1 Introduction 7
1.1 AlGaAs/GaAs Heterojunction Bipolar Transistor 7
1.2 Thermal Effect in an AlGaAs/GaAs HBTs 8
1.3 Surface Passivation of an AlGaAs/GaAs HBT 9
Chapter 2 Background Theory 11
2.1 The Basic Structure and Concept of an AlGaAs/GaAs HBT11
2.2 Heterojunction Properties and Band Discontinuities 13
2.3 Surface Passivation of the HBT 15
2.4 Thermal Effect and Calculation of Lattice Temperature in an AlGaAs/GaAs HBT 16
2.5 The Cut-Off Frequency of HBTs 18
2.6 The Fabrication Technology of HBT 20
Chapter 3 Experiment 22
3.1 Structure of the AlGaAs/GaAs HBT 22
3.2 The Fabrication Process of the HBT 22
3.2.1 Device Isolation 22
3.2.2 Emitter mesa 23
3.2.3 Base Pedestal 23
3.2.4 Emitter Contact 24
3.2.5 Collector Contact 24
3.2.6 Base Contact 25
3.2.7 Insulator Layer and via 25
3.2.8 Metal Pad and Interconnection 26
3.2.9 Ammonium Sulfide Treatment 26
3.3 Basic Measurement Techniques 26
3.3.1 SEM 26
3.3.2 AFM 28
3.3.3 AES 30
3.3.4 XPS 31
3.4 The RF Measurement 33
Chapter 4 Measurement Results and Discussions 34
4.1 Basic Characteristics of the HBT 34
4.1.1 Ohmic Contact and the P-N Junction 34
4.1.2 The DC Performances of the HBT 35
4.2 Thermal Effect on the AlGaAs/GaAs HBT 36
4.2.1 The Thermal Effect on the HBT 36
4.3 The AlGaAs/GaAs HBT with Ammonium Sulfide Treatment 38
4.3.1 The Surface State Improvement of the HBT 38
4.3.2 DC Current Gain Improvement of the HBT 39
4.3.3 Thermal Effect of the HBT with Ammonium Sulfide Treatment 42
4.4 The RF Performances of the AlGaAs/GaAs HBT 43
4.4.1 The Network Analyzer System 43
4.4.2 The Measurement of S-Parameters 44
4.4.3 The Measurement Results of the HBT 45
Chapter 5 Conclusion 47
Chapter 6 Future work 50
Reference 51

Reference[1] Shockley, W., U.S. Patent NO. 2, 569, 347, 1951.[2] Kroemer, H., Theory of a wide-Gap Emitter for Transistors. Proc. IRE, Vol.45, 1957, p. 1535.[3] Kroemer, H., Heterostructure Bipolar Transistor Transistors and Integrated Circuits, Proc. IEEE, Vol.70, 1982, p. 13[4] Asbeck, P. M., et al., Heterojunction Bipolar Transistors for Ultra High Speed Digital and Analog Applications, IEDM Tech. Digest, 1988[5] Liou, L. L., et al., Thermal Stability Analysis of Multiple Finger Microwave AlGaAs/GaAs Heterojunction Bipolar Transistors, IEEE Int. Microwave Symp. Tech. Digest, 1993[6] A.Kapila and V.Malhotra, Surface Passivation of Compound Semiconductors, IEEE, 1997.[7] Houser, J. R., The Effects of Distributed Base Potential on Emitter-Current Injection Density and Effective Base Resistance for Stripe Transistor Geometries, IEEE Trans. Electron Devices, Vol. ED-11, 1964, pp. 238-242[8] Yuan, J. S., and J. J. Liou, Circuit Modeling for Transient Emitter Crowding and Two-Dimensional Current and Charge Distribution Effects, Solid State Electron, Vol. 32, August 1989, pp. 623-631[9] Liou, J. J., F. A. Lindholm, and et al., Modeling the cutoff Frequency of Heterojunction Bipolar Transistors Subjected to High Collector-Layer Current J. Appl. Phys., Vol. 67, 1990, pp. 7125-7131[10] Liou, J. J., An Improved and Analytical Model for the Current Transport in Graded Heterojunction Bipolar Transistors, Solid State Electron, Vol. 38, 1995, p.946[11] Liou, J. J., et al., An Analytical Model for Current Transport in AlGaAs/GaAs Abrupt HBTs with a Setback Layer, Solid State Electron, Vol. 36, 1993, pp. 819-825[12] Mazier, C. M., M. S. Lundstrom, On the Estimation of Base Transit Time in AlGaAs/GaAs Bipolar Transistors, IEEE Electron Device Letter, Vol. EDL-8, 1987, pp. 90-92[13] Azoff, E. M., Energy Transport Numerical Simulation of Graded AlGaAs/GaAs Heterojunction Bipolar Transistors, IEEE Trans. Electron Devices, Vol. 36, 1989, pp. 609-616 [14] Chatterjee, A., et al., Theory of abrupt Heterojunctions in Equilibrium, Solid State Electron, Vol. 24, 1981, pp. 1111-1115[15] Lundstrom, M.S. et al., Modeling Semiconductor Heterojunctions in Equilibrium, Solid State Electron, Vol. 25, 1982, pp. 683-691[16] Unln and Nussbaum, Band Discontinuities as Heterojunction Device Design Parameters, IEEE Trans. Electron Devices, Vol. ED-33, 1986, pp. 616-619[17] Chang, K. M., Band Discontinuities: A Simple Electrochemical Approach, IEEE Trans. Electron Devices, Vol. 37, 1990, pp. 883-886[18] Arnold, D., et al., Determination of the Valence-band Discontinuity Between GaAs and (Al,Ga)As by the Use of P+-GaAs- (Al,Ga)As-P-GaAs Capacitators, Appl. Phys. Lett., Vol.45, 1984, p. 1237[19] Wang, W. I., et al., High Mobility Hole Gas and Valence-Band Offset in Modulation-Doped P-AlGaAs/GaAs Heterojunctions, Appl. Phys. Lett., Vol.45, 1984, p. 639[20] Perlman, S. S., and D. L. Feucht, p-n Heterojunction, Solid State Electron, Vol. 7, 1964, p. 911[21] Lundstom, M. S., Boundary Conditions for p-n Heterojunctions, Solid State Electron, Vol. 27, 1984, p. 491[22] Pulfrey, D. L., et al., Electron Quasi-Fermi Level Splitting at the Base-Emitter Junction of AlGaAs/GaAs HBTs, IEEE Trans. Electron Devices, Vol. 40, 1993, p. 1183[23] W. Liu and J. Harris, Diode Ideality Factor for Surface Recombination Current in AlGaAs/GaAs Heterojunction Bipolar Transistors, IEEE Trans. Electr. Dev. 39, 1992, pp. 2726-2732[24] Liou, J. J., Advanced Semiconductor Device Physics and Modeling, Norwood: Artech House, 1994, Chapter 1[25] Shur, M., Physics of Semiconductor Devices, Englewood Cliffs, NJ: Prentice Hall, 1990[26] Maycock, D. P., Thermal Conductivity of Silicon, Germanium, Ⅲ-Ⅴ Compound and Ⅲ-Ⅴ Alloys, Solid-State Electron., Vol. 10, 1967, P. 161[27] Joyce, W. B., Thermal Resistance of Heat Sink with Temperature-Dependent Conductivity, Solid State Electron., Vol. 18, 1975, P. 321[28] Ali, F., and A. Gupta, eds., HEMTs and HBTs: Devices, Fabrication, and Circuits, Norwood, MA: Artech House, 1991[29] Malik, R. J., et al., Carbon Doping in Molecular Beam Epitaxy of GaAs from a Heated Graphite Filament, Appl. Phys. Lett., Vol. 54, 1989, p. 39[30] Bowler, D. L., and F. A. Lindholm, High Current Regimes in Transistor Collector Region, IEEE, Trans. Electron Devices, Vol. ED-20, 1973, p. 257[31] Kirk, Jr., C. T., A Theory of Transistor Cutoff Frequency Falloff at High Current Densities, IEEE Trans. Vol. Ed-9, 1962, p. 164[32] W. R. Runyan and T. J. Shaffer, Semiconductor Measurements and Instrumentation, The McGraw-Hill Companies, Inc, pp. 279~307[33] W. R. Runyan and T. J. Shaffer, Semiconductor Measurements and Instrumentation, The McGraw-Hill Companies, Inc, pp. 386~389[34] W. R. Runyan and T. J. Shaffer, Semiconductor Measurements and Instrumentation, The McGraw-Hill Companies, Inc, pp. 357~377[35] T. A. Carlson, Photoelectron and Auger Spectroscopy, Plenum Press, New York, 1975[36] C.S. Fadley, Basic Concepts in X-Ray Photoelectron Spectroscopy, in Electron Spectroscopy: Theory, Techniques and Applications, Vol.2, Academic Press, New York, 1978, pp. 2~156[37] P.K. Gosh, Introduction to Photoelectron Spectroscopy, Wiley-Interscience, New York, 1983[38] D. Briggs and M.P. Seah, Practical Surface Analysis by Auger and X-Ray Photoelectron Spectroscopy, Wiley, New York, 1983[39] J. B. Lumsden, X-Ray Photoelectron Spectroscopy, in Metals Handbook, Ninth Ed, Am. Soc. Metals, Metals Park, OH, 10, pp. 568~580, 1986[40] N.Martensson, ESCA, in Analytical Techniques for Thin Film Analysis, Academic Press, San Diego, CA, 1988, pp. 65~109 [41] C. Nordling, K. Siegbahn, et al, Application of Electron Spectroscopy to Chemical Analysis, Z. Phys. Vol. 178, pp. 433~438, 1964[42] C. Nordling, K. Siegbahn, et al, Electron Spectroscopic Determination of the Chemical Valence State, Z. Phys. Vol. 178, pp.439~444, 1964[43] Hayrettein Yuzer, Hacer Dogan, et al, Analysis of Sulfide Layer on Gallium Arsenide Using X-ray Photoelectron Spectroscopy Spectrochemical ACTA PARTB55, pp.991~996, 2000[44] Z. L. Yuan, X.M. Ding, et al, Investigation of Neutralized (NH4)2S Solution Passivation of GaAs (100) surfaces, American Institute of Physics, pp3081~3083, 1997[45] J. Gillespie, C. Bozada, et al, Passivated InGaP/GaAs Heterojunction Bipolar Transistor Technology using Pt/Ti/Pt/Au Base Contacts, IEEE, 1997, III-4, pp.99~108[46] Guido Hirsch, Peter Kruger, and Johannes Pollmann, Surface Passivation of GaAs (001) by Sulfur: an Initial Studies, Surface Science, 1998, pp.778~781[47] A. B. M. O. Islam, T. Tambo, and C. Tatsuyama, Passivation of GaAs Surface by GaS, VACUUM, 2000, pp. 894~899[48] Y. Dong, X. M. Ding and X.Y. Hou, Sulfur Passivation of GaAs Metal-Semiconductor Field-Effect Transistor, Applied Physics Letters, Vol. 77, Num. 23, 2000, pp. 3839~3841[49] Vasily N. Bessolov, et al, Sulfidization of GaAs in Alcoholic Solutions: a Method having an Impact on Efficiency and Stability of passivation, Meterials Science & Engineering, B44, 1997, pp. 376~379[50] H. H. Lee, et al, Surface Passivation of GaAs, Appl. Phys. Lett. 54 (8), 20 Feb. 1989, pp724~726[51] B.A. Cowans, et al, X-ray Photoelectron Spectrodcopy of Ammonium Sulfide Treated GaAs (100) Surfaces, Appl. Phys. Lett. 54 (4), 23, Jan., 1989, pp. 365~367[52] J.Yota and V. A. Burrows, Chemical and Electrochemical Treatments of GaAs with Na2S and (NH4)2S Solutions: A Surface Chemical Study, J. Vac. Sci. Technol. A 11 (4), Jul/Aug, 1993, pp.1083~1088[53] X.Y. Hou, W. Z. Cai, et al, Electrochemical Sulfur Passivation of GaAs, Appl. Phys. Lett. 60 (18), 4 May, 1992, pp. 2252~2254[54] B. A. Kuruvilla, A. Datta, et al, Atomic Force Microscopy of Selenium Sulfide Passivated GaAs (100) Surface, Appl. Phys. Lett. 69 (3), 15 July, 1996, pp. 415~417[55] Juin J.Liou，Principles and Analysis of AlGaAs/GaAs Heterojunction Bipolar Transistors[56] William Liu，Fundamentals of Ⅲ-Ⅴ Devices HBTs，MESFETs，and HFETS/HEMTS[57] A.Kapila and V.Malhotra，Surface Passivation of Compound Semiconductors，IEEE，1997[58] J.Yota and V.A.Burrows，Chemical and Electrochemical Treatments of GaAs with Na2S and (NH4)2S Solutions: A Surface Chemical Study，American Vacuum Society，1993[59] N.Yamamoto，K.Kishi, Ammonium Sulfide Combined Etching(ACE):an Effective Treatment for Reducing Impurities Prior to MOVPE InP Regrowth in a Process using Hydrocarbon Gas Reactive Ion Etching(RIE)，Journal of Crystal Growth 193，1998，16~22[60] Harettin Yuzer，Hacer Dogan，Analysis of Sulfide Layer on Gallium Arsenide Using X-ray Photoelectron Spectroscopy，Spectrochemica Acta Part B 55 ，2000 991~996[61] P.G.Neudeck，M.S.Carpenter，Significant Long-Term Reduction in n-Channel MESFET Subthreshold Leakage Using Ammonium-Sulfide Suface Treated Gates，IEEE RLECTRON DEVICE LETTERS，Vol.12，NO.10，OCT.1991[62] C. J. Sandroff, R. N. Nottenburg, J.-C. Bischoff, and R. Bhat，Dramatic Enhancement in the Gain of a GaAs/AlGaAs Heterostructure Bipolar Transistor by Surface Chemical Passivation，Appl. Phys. Lett. 51(1), 6 July 1987 pp33~35[63] Sanguan Anantathanasarn, et al, Surface Passivation of GaAs by Ultra-Thin Cubic GaN Layer, Applied Surface Science, 2000, pp.159~160[64] Min-Gu Kang, et al, Pretreatment of GaAs (001) for Sulfur Passivation with (NH4)2Sx, Thin Solid Films, 1996, pp.328~333[64] Hann-Ping Hwang, et al, A Comparative Study of the Passivation Films on AlGaAs/GaAs Heterojunction Diodes and Bipolar Transistors, IEEE Transactions on Electron Devices, VOL. 48, NO. 2, Feb., 2001, pp. 185~189[65] Hong Wang, et al, Understanding the Degradation of InP/InGaAs Heterojunction Bipolar Transistors Induced by Silicon Nitride Passivation, 2001 IPRM conference Proceedings, 13th IPRM 14-18, May 2001 Nara, Japan[66] R. T. Yoshioka, et al, Improving Performance of Microwave AlGaAs/GaAs HBTs Using Novel SiNX Passivation Process, SBMO/IEEE MTT-S IMOC’99 Proceedings, 1999, pp. 108~111[67] Yousef Zebda and Omar Qasaimeh, Currents and Currents Gain Analysis of Passivated Heterojunction Bipolar Transistors (HBT), Transactions On Electron Devices, IEEE, Vol. 41. NO.12, DEC. 1994, pp. 2233~2240[68] C. MANEUX, et al, Analysis of the Surface Base Current Drift in GaAs HBT’s, Microelectron. Reliab, Vol. 36, 1996, pp. 1903~1906[69] R. E. Welser, et al, High Performance Al0.35Ga0.65As/GaAs HBT’s, IEEE Electron Device Letters, Vol. 21, NO. 5, May 2000, pp. 196~199[70] G. Jackson, et al, High Gain, Pulsed Power AlGaAs/GaAs HBTs, Solid-state Elec., Vol. 38, No. 9, 1995, pp. 1641~1644[71] Il-Ho Kim, Effects of Emitter Structure Variation on the RF Characteristics of AlGaAs/GaAs HBTs, Materials Letters, Vol. 49, 2001, pp. 219~223[72] K. Mochizuki, et al, AlGaAs/GaAs HBTs with Buried SiO2 In The Extrinsic Collector, Solid-state Elec., Vol. 38, NO. 9, 1995, pp. 1619~1622[73] Bin Li, Sheila Prasad, et al, A numerical Study of AlGaAs/GaAs HBTs, Solid-State Electro., Vol. 43, 1999, pp. 839~843[74] A. Kager, et al, A Numerical Study of the Effect of Base and Collector Structures on the Performance of AlGaAs/GaAs Multi-finger HBTs, Solid-State Elec., Vol. 38, No. 7, 1995, pp.1339~1349