跳到主要內容

臺灣博碩士論文加值系統

(44.200.27.215) 您好!臺灣時間:2024/04/15 04:00
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

: 
twitterline
研究生:陳怡帆
研究生(外文):Chan, Yi-Fan
論文名稱:氮化鎵缺陷能階為0.5eV的電性研究
論文名稱(外文):Electronic properties of the Ec-0.5 eV defect level in GaN
指導教授:陳振芳陳振芳引用關係
指導教授(外文):Chen, Jenn-Fang
學位類別:碩士
校院名稱:國立交通大學
系所名稱:電子物理系所
學門:自然科學學門
學類:物理學類
論文種類:學術論文
論文出版年:2009
畢業學年度:97
語文別:中文
論文頁數:63
中文關鍵詞:氮化鎵缺陷能階深層能階暫態頻譜儀
外文關鍵詞:GaNdefect levelDLTS
相關次數:
  • 被引用被引用:0
  • 點閱點閱:260
  • 評分評分:
  • 下載下載:59
  • 收藏至我的研究室書目清單書目收藏:0
本論文主要是藉由電性的量測,包括電流電壓 (I-V)、電容電壓 (C-V)、導納頻譜 (C-F&G-F)、深層能階暫態頻譜儀 (DLTS) 的量測來探討氮化鎵在電性上的表現。
本研究一開始主要在探討成核層上的腔體壓力條件,由x-ray diffraction得知以高壓的腔體環境磊晶氮化鎵成核層其樣品品質較好,但透過電性量測的結果得知未摻雜的氮化鎵本身是具有高阻值的材料特性,以至於電性量測受到高阻抗的影響而使得DLTS無法量測出缺陷訊號。雖然改善其成核層上的壓力升至高壓時,其阻值降低了一個數量級,在DLTS我們的確也量測到一個相同的缺陷能階 (樣品808 & 811),但由於此訊號過於微弱,於是我們另外磊晶一層n型氮化鎵材料介於成核層與未摻雜的氮化鎵之中來改善其樣品特性。
研究結果得知此n型材料的形成將有助於降低未摻雜氮化鎵的阻值達3個數量級。另外,反應在蕭基二極體電流中,其電流的傳導機制也將以thermionic emission為主導。同樣的我們在此n型摻雜的樣品中量到了與樣品808及811相同的缺陷能階,文獻研究認定此缺陷與氮錯位有關,加上此樣品在電性表現上其結果都較其他樣品好,於是我們透過此樣品針對這一0.5 eV的缺陷能階作更進一步的研究討論。
在DLTS量測上我們發現此缺陷具有差不多的emission barrier及capture barrier。其emission barrier是在導電帶下方約0.5 eV,捕獲截面積為10-16 cm2。藉由改變filling pulse width (tp) ,其emission barrier不隨缺陷內載子濃度改變,但capture barrier將受到缺陷內載子濃度而大幅度變化。為了更進一步研究此缺陷的電性行為,我們引用Tadeusz Wosinski[1]所提出的缺陷理論分析,求得缺陷內無電子為empty能態時的能障高度為0.37 eV。文獻研究指出此缺陷為氮原子取代鎵空穴而成( ),於是我們大膽假設此缺陷會產成一個類似Schottky的intrinsic barrier height 為0.52 eV( )。換言之,缺陷的表現使得費米能階被pin在相同位能,而使得此缺陷同時具有emission等於capture 的相同能障,表現出dot-like defect的電性特質。
We have investigated the GaN films grown on sapphire substrates by metal-organic chemical vapor deposition (MOCVD) such as unintentionally GaN and intentionally Si-doped GaN above the nucleation layer. Deep level transient spectroscopy (DLTS) measurements on both samples reveal a same defect level. At~0.5 eV whose electron emission and capture mechanism in DLTS are investigated.
For unintentionally doped sample, we modulated the growth pressure condition in the nucleation layer. The unintentional-doped low pressure nucleation layer exhibits highly resistive with 105 Ω, probably preventing the DLTS spectra from revealing trapping signals. On the other hand the DLTS measurement on the high pressure nucleation layer sample exhibits the defect level.
For intentionally Si-doped sample grown between the nucleation layer and undoped
GaN, the resistivity is reduced to 100 Ω, allowing us to study defect characteristics by DLTS measurement.
The DLTS spectra exhibits a majority carrier trap with apparent energy close to 0.5 eV below conduction band, capture cross section of about 10-16 cm2 and the trap concentration of 1013 cm2. A comparison with previous literature suggests that this level is probably related to nitrogen antisite. By modulating filling pulse duration (tp), the DLTS peak temperature remains unchanged. Therefore, the electron emission barrier is not affected by trap concentration and is remained at 0.5 eV.
The capture behaviors of the defect were investigated. We find that the defect has a capture barrier which is similar as the emission barrier for a similar time constant. The DLTS peak shifts toward a lower temperature with increasing tp. This result shows that the capture barrier is affected by the electron concentration. From extrapolation, the defect in an empty state has an intrinsic barrier height of 0.52 eV , suggesting that the defect behaves like a dot and the defect is clustered, which pins the Fermi level at a value that corresponds to the emission barrier height.
From the result of our experiments, we have demonstrated that the intentionally Si doped sample exhibits good electrical characteristics. The 0.5 eV level exhibits a dot-liked defect and behaves like clusters, rather than an isolated point defect.
目錄

中文摘要……………………………………………………………………………I
英文摘要………………………………………………………………………… Ⅲ
致謝……………………………………………………………………………… Ⅴ
目錄……………………………………………………………………………… Ⅶ
圖目錄…………………………………………………………………………… Ⅸ
表目錄………………………………………………………………………………… ⅩⅡ
第一章 緒論……………………………………………………………… 1
第二章 文獻回顧與樣品製備…………………………………………… 2
2-1發光二極體的歷史……………………………………………………………2
2-2氮化鎵材料……………………………………………………………………3
2-3硬壓力與張壓力………………………………………………………………4
2-4 有機金屬化學氣相磊晶法……………………………………………………5
2-5蕭基二極體之製成…………………………………………………………… 6
2-6研究動機……………………………………………………………………… 7
2-7論文架構……………………………………………………………………… 7
第三章 實驗儀器介紹……………………………………………………15
3-1電流電壓量測 (I-V)……………………………………………………… 15
3-2電容電壓量測 (C-V)……………………………………………………… 17
3-3導納頻譜量測 (C-F)……………………………………………………… 17
3-3.1 缺陷在不同頻率下對導納(admittance)量測的影響……………………17
3-3.2 串聯電阻對導納(admittance)量測的影響………………………………18
3-4 深層能階暫態頻譜量測(DLTS)……………………………………………19
3-4-1測量缺陷捕捉截面積與活化能……………………………………… 20
第四章 實驗數據及討論…………………………………………………25
4-1 調變無摻雜的成核層與磊晶層之電性研究………………………………25
4-1.1 成長樣品的目的性…………………………………………………… 25
4-1.2 樣品結構圖…………………………………………………………… 25
4-1.3 XRD及其SEM之結果……………………………………………………26
4-1.3 蕭基二極體電流分析………………………………………………… 26
4-1.5 串聯電阻的量測……………………………………………………… 26
4-1.6 暫態深層能階量測(DLTS)…………………………………………… 27
4-2 Nitrogen antisite defect level的電性探討………………………… 28
4-2.1 I-V與C-V量測……………………………………………………… 28
4-2.2 DLTS Measurement by emission pulse………………………………29
4-2.3 DLTS Measurement by capture pulse……………………………… 30
4-2.4 DLTS量測機制探討……………………………………………………31
4-2.5 Nitrogen antisite defect model ………………………………………...32
第五章 結論 …………………………………………………………… 59
第六章 參考文獻…………………………………………………………61
[1] Tadeusz Wosinski, ”Evidence for the electron traps at dislocations in GaAs crystals” J. Appl. Phys., Vol. 65,1566 (1989)
[2] Jonathan Michael Hayes MSci, “Raman Scattering in GaN, AlN,AlGaN: Basic Material Properties, Processing and Devices”(2002)
[3] H. Morkoc, S. Strite, G. B. Gao, M. E. Lin, B. Sverdlov, M. Burns, J. Appl. Phys., Vol. 76 , 1363, (1994)
[4] T. Lei, K. F. Ludwig, T. D. Moustakas, J. Appl. Phys., Vol. 74, 4430 (1993)
[5] H. Amano, N. Sawaki, and I. Akasaki,” Metalorganic vapor phase epitaxial growth
of a high quality GaN film using an AlN buffer layer” Appl. Phys. Lett. vol.48,353
(1986)
[6 ] H. Amano, M. Kito, K. Hiramatsu, I. Akasaki, Jpn. J. Appl. Phys., Vol. 28, No. 12, L2112 (1989)
[7] I. Akasaki, H. Amano, Y. Koide,K.Hiramatsu and N. Sawaki:J. Cryst. Growth 98(1989) 209.
[8] Shuji Nakamura,” GaN Growth Using Buffer Layer” Jpn. J. Appl. Phys., Vol. 30, No. 10A, L1705 (1991)
[9] P. Boguslawski , E. L. Briggs and J. Bernholc ”Native defects in gallium nitride, Phys. Rev. B ,Vol.51, 17255 (1995).
[10] K. Hiramatsu, T. Detchprohm, I. AKasaki, Jpn. J. Appl. Phys., Vol. 32, No. 4, 1528 (1993)
[11] A. C. Warren, J. M. Woodall. J. L. Freeouf, D. Grischkowsky “Arsenic precipitates and the semi-insulating properties of GaAs buffer layers grown by low-temperature molecular beam epitaxy” Appl. Phys. Lett. Vol. 57,1331 (1990)
[12] W. Schroter, J. Kronewitz, U. Gnauert, F. Riedel, and M. Seibt, ” Bandlike and localized states at extended defects in silicon”, Phys. Rev. B ,Vol.52, 13726 (1995).
[13] W.D. Nix and B.M. Clemens, ”Crystallite coalescence: A mechanism for intrinsic tensile stresses in thin films”, Journal of Materials Research,Vol.14, 3467(1999)
[14] T. L. Tansley and R. J. Egan ”Point-defect energies in the nitrides of aluminum , gallium, and indium”, Phys. Rev. B ,Vol.45, 10942 (1992).
[15] ”Semiconductor Physics and Devices” by Donald A. Neamen, third edition , Chapter 9, “Metal-Semiconductor and Semiconductor Heterojunctions”
[16] A. C. Schmitz, A. T. Ping, M. Asif Khan, Q. Chen, J. W. Yang, and I. Adesida, ” Metal Contacts to n-Type GaN ”,Journal of Electronic Materials, Vol.27,No.4(1998)
[17] C. A. Mead and W. G. Spitzer, ”Fermi Level Position at Metal-Semiconductor Interfaces ”, Phys. Rev. B ,Vol.134, A713 (1964).
[18] A. M. Cowley and S. M. Sze, ”Surface States and Barrier Height of Metal Semiconductor System”, J. Appl. Phys,Vol.36,3212(1965)
[19] D. Pugh,” Surfaces States on the <111> Surfaces of Diamond”, Phys. Rev. Lett. Vol. 12,390(1964)
[20] E. Schibli and A. G. Milnes,” Effects of deep impurities on n+p junction reverse biased small-signal capacitance”, Solid-St. Electron.Vol.11,323(1968)
[21] G. I. Roberts and C.R. Crowell,” Capacitance Energy Level Spectroscopy of Deep-Lying Semiconductor Impurities Using Schottky Barriers”, J. Appl. Phys. Vol.41,1767(1970)
[22] W. G. Oldham and S. S. Naik,” Admittance of p-n junctions containing traps ”, Solid-St.Electron.Vol.15,1085(1972)
[23] T. Mattila, A. P. Seitsonen ,and R. M. Nieminen, ”Large atomic displacements associated with the nitrogen antisite in GaN” Phys. Rev. B, Vol. 54,1474 (1996)
[24] D.V. Lang, “Deep-level transient spectroscopy: A new method to characterize traps in semiconductors”, J. Appl. Phys. Vol.45, 3023 (1974).
[25] Dieter K. Schroder, “Semiconductor Material and Device Characterization”-2nd ed. (New York :Wiley 1998).
[29] J. H. Jang, A. M. Herrero, B. Gila, C. Abernathy,and V. Craciun,” Study of defects evolution in GaN layers grown by metal-organic chemical vapor deposition” J. Appl. Phys., Vol. 103, 063514 (2008)
[30] H. K. Cho, C. S. Kim, and C. H. Hong,” Electron capture behaviors of deep level traps in unintentionally doped and intentionally doped n-type GaN” J. Appl. Phys., Vol. 94,1485 (2003)
[31] H. K. Cho, K. S. Kim, and C. H. Hong, H. J. Lee,” Electron traps and growth rate of buffer layers in unintentionally doped GaN” Journal of Crystal Growth , Vol . 223 , 38-42 (2001)
[32] T. Wang,T. Shirahama,H. B. Sun, H. X. Wang ,J. Bai and S. Sakai,” Influence of buffer layer and growth temperature on the properties of an undoped GaN layer grown on sapphire substrate by metalorganic chemical vapor deposition” Appl. Phys. Lett. Vol.76,2220(2000)
[33] A. Krtschil,H. Witte,M. Lisker, and J.Christen,” Analysis of deep traps in hexagonal molecular beam epitaxy –grown GaN by admittance spectroscopy” J. Appl. Phys., Vol. 84,2040 (1998)
[34] P. Hacke, T. Detchprohm, K. Hiramatsu, and N. Sawaki,” Analysis of deep levels in n-type GaN by transient capacitance methods” J. Appl. Phys., Vol. 76,304 (1994)
[35] Julien Pernot and Pierre Muret,” Electronic properties of the Ec-0.6 eV electron trap in n-type GaN” J. Appl. Phys., Vol. 103,023704 (2008)
[36] Z-Q. Fang and D. C. look, W. Kim and Z. Fan, A. Botchkarev and H. Morkoc,” Deep centers in n-GaN grown by reactive molecular beam epitaxy” Appl. Phys. Lett. Vol.72,2277(1998)
[37] Z.-Q. Fang, J.W. Hemsky and D. C. look,” Electron-irradoation-induced deep level in n-type GaN” Appl. Phys. Lett. Vol.72,448(1998)
[38] W. I. Lee and T. C. Huang,” Effects of column III alkyl sources on deep levels in GaN grown by organometallic vapor phase epitaxy” Appl. Phys. Lett. Vol.67,1721(1995)
[39] W. Gotz and N. M. Johnson,” Deep level defects in n-type GaN” Appl. Phys. Lett. Vol.65,463(1994)
[40] Peter Hacke,Atsuyoshi Maekawa,Norikatsu Koide,Kazumasa Hiramatsu,” Characterization of the Shallow and Deep Levels in Si Doped GaN Grown by Meral-Organic Vapor Phase Epitaxy” Jpn. J. Appl. Phys. Vol.33,6443(1994)
[41] A. Broniatowski, A. Blosse, P. C. Srivastava and J. C. Bourgoin. “Transient capacitance measurements on resistive samples” J. Appl. Phys. Vol.54,2907(1983)
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top