摘要

本論文中，我們利用三氯化硼和氯氣混和氣體以電感耦合電漿蝕刻對氮化鋁鎵做蝕刻特性探討，發現當三氯化硼和氯氣混和氣體的比率幾乎相等時得到最大蝕刻速率為600nm/min和最佳的表面粗糙度RMS 4.5nm。而且蝕刻表面經過回火後表面粗糙度大幅改善。此外，我們成功的製作出氮化鋁鎵調變摻雜場效電晶體，並分析其直流和高頻特性。在直流方面，我們得到元件最高轉導為110mS/mm，最高飽和電流為480mA/mm及4伏特的工作平台。在高頻部分我們以8510網路分析儀得到2.5GHz的截止頻率及5.3GHz的最大共振頻率。此外，我們利用嵌入埋藏鎂摻雜氮化鎵和氮化鋁鎵超晶格來做絕緣層以降低漏電流的發生及得到較低的膝電壓1V。
另外，我們利用突波電流-電壓量測證明以藍寶石為基板成長的氮化鋁鎵電晶體存在自我熱效應會造成元件的退化，使得在高汲極電壓時，汲極電流反而降低。當電壓的突波時間增加時發現電晶體特性有退化的趨勢。另外我們也做了一組變溫的量測，發現隨著溫度升高，轉導值和飽和電流都會因為高溫造成雜質散射效應而降低。不過當溫度達300oC時仍保有很好的電晶體特性且轉導值仍有40mS/mm，證明這材料適於高溫、高功率的應用。

Abstract

In this thesis, we etch AlGaN bulk materials by ICP system to investigate the properties on BCl3 and Cl2 reactive mixtures. We obtain the maximum etch rate (600nm/min) and best surface roughness RMS (4.5nm) only when the BCl3 and Cl2 ratio is equal. And annealing can highly improve the surface roughness. In addition, we had successfully fabricated the DC and RF AlGaN/GaN(MODFET). At DC section, the maximal transconductance (Gm) is 110mS/mm, saturation current reach 500mA/mm and gate-voltage-swing is 4V, it mean the device can operate at wide range. At RF section, we obtain cut-off frequency fT =2.5G and the maximum oscillation frequency fmax is 5.3G by HP 8510C network analyzer. Besides, We make use of embedding a unactived Mg-doped GaN and AlGaN superlattice to be the insulating layers, which can decrease the leakage current, and get lower knee voltage.
In addition, we use pulse I-V to prove the self-heating effect on the AlGaN/GaN (MODFET). When we increase the pulse period would result in the current degradation. We measure I-V curve at different temperatures and found the transconductance and saturation current also decrease with the increase of temperatures. However, the device can still normal operate at 300oC with transconductance (40mS/mm). It prove that this material can endure high temperature and highly enhance it’s applications on high temperature and high power.

Reference 1
[1].T.Lei,T.D.Moustakas,R.J.Graham,Y.He,and .J.Berkowitz,Jappl.Phys.71(1992)4993
[2].P.C.Joh,J.J.Alwan and J.G. Eden,Thin SolidFilm,218,75(1992)
[3].T.Sasaki and T.Matsuoka,J.Appl.Phys.64,4531(1988)
[4].P,J.Born and D.S.Robertson,J.Mater.Sci.15,3003(1980)
[5].T. Detchprohm, Hamano, K. Hiramatsu, and I. Akasaki, J.Crust.Growth, 128, 384 (1993)
[6].R.C.Powell,G.A.Tomasch,Y.W.Kim,J.A.Thornton,andJ.E.Greene, Mater. Res. Soc. Symp. Proc.162, 525(1990)
[7]. T. Detchprohm, K.Hiramatsu, N.Sawaki, and I. Akasaki, J. Crust.Growth, 137,170(1994)
[8].S.Nakamura and G. Fasol, ”The Blue Laser Diode”,pp.7~16,1997
[9].A. Bykhovski, B. Gelmont, and M.Shur,J.Appl. Phys. 74,6734(1993)
[10].P. Kozodoy, M. Hansen,S.P.DenBaars,and U.K.Mishra,Appl. Phys. Lett.74,3681(1999)
[11].M.A.Khan,Q.Chen,M.S.shur,B.t. Dermott,J.A.Higgins,J. Burm,W. Schaff, and L.F. Eastman,Electron. Lett.32, 357(1996)
Reference 2
[1]. Gregory S. Marlow, Mukunda B. Das, “The effects of contact size and non-zero resistance on the determination of speeific contact resistance. “Solid State Electronics, Vol. 25, No. 2, P. 91~94, 1982.
[2]. R.K. Willardson and A,C, Beer, Semiconductors and Semimetals, Vol. 7,pp. 175-183 . Academic Press, Ner York (1971).
[3]. V. Ya. Niskov and G. A. Kuberskii, Resistance of ohmic contacts between metal and semiconductor films. Sov. Phys. Semicond. 4, 1553 (1971).
[4].W.G. Bickley, Bessel Functions, pp. 220-255. University Press, Cambridge (1960).
[5]. S. S. Cohen and G. Sh. Gildenblat, VLSI Electronics, 13, Metal-Semiconductor Contacts and Devices, Academic Press, Orlando, FL, 1986, 115.
[6]. M. Ahmad and B.M. Arora, “Investigation of AuGeNi Contacts Using Rectangular and Circular Transmission Line Model, “Silid-State Electron. 35, 1441-1445, Oct. 1992.
[7]. I. Adessida, A. Mahajan, E. Andideh, M. A. Kahn, D. T. Olson, and J.N. Kuznia, Appl. Phys. Lett. 63,2777(1993)
[8]. S. J. Pearton, C. R. Abernathy, F. Ren, J.R.Lothian,J. Vac. Sci. Technol.A 11,1772(1993).
[9]. R.J. Shul, G.B. McClellan, S.A. Casalnuovo, D.J. Rieger, Appl. Phys. Lett.69, 1119 (1996)
Reference 3
[1]. J. I. Pankore,J. Electrochem,Soc,119(1972) 1110.
[2]. S. T. Pearton and C.R. Abernathy, Appl. Phys. Lett, 64(1994) 2294
[3]. M. E. Lin, Appl. Phys, Lett,64(1994)887
[4].I.Adesida,A. Mahajan, and E. Andideh, Appl. Phys.Lett,63(1993)2777
[5].Y. H. Lee, H. S. Kim, G. Y. Yeom, J. W. Lee, W. C. Yoo, T. I. kim, Journal of Vacuum Science Technology A, vol.16, no.3, pp.1478-1482, 1998
[6].R. J. Shul, R. P. Schneider, Jr. and C. Constantine, Electronics Letters, vol.30,no.10,pp.817-819,1994
Reference 4
[1].M. A. K han, Q. Chen, M. S. Shur, B. T.McDermott,J. A. Higgins, J.Burm, W. J. Schaff, and L. F. Eastman, IEEE Electron dDevice Lett.17,584(1996)
[2].A. Ozgur, W. Kim, Z. Fan, A. Botchkarev, A Salvador, S. N. Mohammad, B. Sverdlov, and H.Morkoc,Electron.Lett.31,1389(1995)
[3].W. Q. Chen and S. K.Hark,J.Appl.Phys.77,5747(1995)
[4].A.Bykhovski,B.L.Gelmont,andM. S. shur, J.Appl.Phys.91,6332(1997)
[5].國立成功大學碩士論文Epitaxy of GaN by MOCVD and Fabrication of AlGaN/GaN MODFET by Chang-Yi Yang and Yan-Kuin Su
Reference 5
[1].T. P. chow and R. Tyagi, IEEE Trans.Electron Devices 41, 1481(1994)
[2].H.Morkoc, S. Strites, G. B. Gao. M.E. Lin, B. Sverdlov, and M. Burns,J. Appl.Phys, 76, 1363(1994)
[3].S. C. Binari, B. L. Rowland, W. Kruppa, G.. Kelner, K. Doverspike, and D. K. Gaskill, Electron. Lett.30, 1248(1994)
[4].O.Akutas, Z. F. Fan,S. N. Mohammad, A. E. Botchkarev, and H. Morkoc, Appl. Phys. Lett.69,3872(1996)