具快速逆向回復時間之矽基600伏氮化鋁鎵/氮化鎵蕭基二極體

A 600V AlGaN/GaN Schottky Barrier Diode(SBD)on Si Substrate with Fast Reverse Recovery Time

柯宗佑(Tsung-Yu Ke)

指導教授 ： 辛裕明

國立中央大學/資訊電機學院/電機工程學系/碩士(2011年)

摘要

本論文利用2 μm的緩衝層將氮化鎵鋁/氮化鎵異質接面層成長於4英吋p型的Si(111)基板上，成功製作出平面式氮化鎵鋁/氮化鎵蕭基二極體。
藉由原子力顯微鏡量測氮化鎵薄膜成長於矽基板的蝕刻孔洞密度(EPD)大約是1.92×109 cm-2；針對氮化鎵成長於Si(111)基板上，我們利用x-ray量測其GaN(002)反射面的繞射轉動曲線，可得到半波高全寬值(FWHM)為536 arc-sec，影響螺旋缺陷密度與材料中漏電流的多寡；最後經由試片的霍爾量測，氮化鎵鋁/氮化鎵異質接面通道的遷移率為1430 cm2 /V-s、片載子密度為9.8?1012 cm-2。
氮化鎵鋁/氮化鎵蕭基二極體元件的製作，歐姆電極的金屬利用鈦/鋁/鎳/金、蕭特基電極利用鎳/金，元件設計方式將歐姆電極等距離的沉積在蕭特基電極的兩邊，針對蕭特基到歐姆電極之間的距離(LGS)以10 ~ 30 μm的改變進行研究討論。對於LGS = 10 μm的元件可量測到特徵開啟電阻(RON)為1.3 mΩ-cm2、電流密度達100 A/cm2下的順偏開啟電壓為1.4 V，元件在沒有任何邊緣終端設計的製作下，於室溫量測下的逆偏崩潰電壓(VB)可高於600 V以上，但元件量測到的崩潰變壓值並沒有隨著LGS的改變而呈現線性的變化，原因在於基板磊晶結構的緩衝層中。評量因子定義為(VB)2/RON，計算後為277 MWcm-2，製程元件在無封裝的環境下量測其開關特性，順偏電流密度大小為720 A/cm2 (總輸入電流大小為1 A)、瞬間以100 A/μs的斜率遞減將元件操作至逆偏30 V後關閉，過程中量測其逆向回復時間小於10 ns。

關鍵字

氮化鎵 ； 氮化鎵鋁 ； 蕭基二極體 ； 逆向回復時間

並列摘要

Lateral AlGaN/GaN Schottky Barrier Diodes (SBDs) on Si substrate have been fabricated and characterized. AlGaN/GaN hetero-junction layers were grown on 4-inch p-type Si (111) substrate with 2 ?m buffer layer.
The measurement of etching pit density (EPD) of GaN films on Si substrate is about 1.92×109 cm-2 by atomic force microscopy (AFM). The full width at half maximum value (FWHM) of x-ray diffraction rocking curve for the GaN film on Si (111) substrate is 536 arc-sec (002 reflection), which is related to the screw type dislocation and resulted leakage current. The Hall measurement showed the mobility of 1430 cm2 /V-s with a sheet carrier density of 9.8?1012 cm-2 for the AlGaN/GaN structure across the wafer.
The AlGaN/GaN SBDs were implemented by Ti/Al/Ni/Au Ohmic and Ni/Au Schottky contacts. The Ohmic contacts were deposited on both side of Schottky contact with equal distance. The Schottky-to-Ohmic contact distance (LGS) was varied from 10 to 30 ?m in this study. The specific on-state resistance (RON) was 1.3 m?-cm2, while the forward turn-on voltage was 1.4 V at the current density of 100 A/cm2 for device with LGS = 10 ?m. The measured reverse breakdown voltage (VB) at room temperature was up to 600 V without edge terminal scheme. The measured VB is not function of LGS, which mainly depends on the buffer layer structure.
The figure-of-merit is defined (VB)2/RON, that was 277 MWcm-2. And reverse recovery time was < 10 ns for device (without package) switched from a forward current density of ~720 A/cm2 (1 A) to a reverse bias of 30 V with di/dt of 100 A/?s.

並列關鍵字

reverse recovery time ； GaN ； AlGaN ； Schottky barrier diode

參考文獻

[26] 游承儒, "高壓氮化鋁鎵/氮化鎵高電子遷移率電晶體製作與分析," 碩士論文, 國立清華大學, 2010.

[1] Chow T. Paul and Tyagi Ritu, "Wide Bandgap Compound Semiconductors for Superior High-Voltage Unipolar Power Devices," IEEE Transactions on Electron Devices, vol. 41, pp. 1481-1483, 1998.

[2] M. Trivedi and K. Shenai, "Performance evaluation of high-power wide band-gap semiconductor rectifiers," Journal of Applied Physics, vol. 85, pp. 6889-6897, 1999.

[3] K. Takatani, et al., "AIGaN/GaN Schottky-ohmic combined anode field effect diode with fluoride-based plasma treatment," Electronics Letters, vol. 44, pp. 320-321, 2008.

[5] G. D. A. P. Zhang, F. Ren, J. Han, A. Y. Polyakov, N. B. Smirnov, A. V. Govorkov, J. M. Redwing, H.Cho and S. J. Pearton, "Temperature dependence and current transport mechanisms in AlxGa1−xN Schottky rectifiers," Applied Physics Letters, vol. 76, p. 3816, 2000.