npsm 새물리 New Physics : Sae Mulli

pISSN 0374-4914 eISSN 2289-0041


Research Paper

New Physics: Sae Mulli 2017; 67: 1162-1167

Published online October 31, 2017

Copyright © New Physics: Sae Mulli.

Growth of $\beta$-Ga$_2$O$_3$ Thin Films by Using Metal-Organic Chemical Vapor Deposition and Their Photocurrent Characteristics

MOCVD를 이용한 $\beta$-Ga$_2$O$_3$ 박막의 성장과 광전류 특성 조사

Seo Young LEE1, Hyung Soo AHN1, Min YANG*1, Young Moon YU2

1 Department of Electronic Material Engineering, Korea Maritime and Ocean University, Busan 49112, Korea
2 LED-Marine Convergence Technology R&BD Center, Pukyong National University, Busan 48547, Korea


Received: July 14, 2017; Revised: August 28, 2017; Accepted: August 28, 2017

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


The characteristics of Schottky diodes fabricated with $\beta$-Ga$_2$O$_3$ thin films grown by using metal-organic chemical vapor deposition (MOCVD) at different growth temperatures were studied. Thin films grown at 600 $^\circ$C and 900 $^\circ$C had quite different surface roughnesses. The surface morphology of the film grown at 600 $^\circ$C was very smooth while that of the film grown at 900 $^\circ$C showed a rough surface with large polycrystalline grains. The current-voltage characteristics of the Schottky diodes fabricated with those thin films and Ti/Au metal electrodes were evaluated. The film grown at 600 $^\circ$C, which had a smooth surface, had a lower cut-in voltage and dark current compared to the film grown at 900 $^\circ$C. Accordingly, the electrical properties of the Schottky diodes were highly affected by the surface roughness and the oxidization during growth. Also, photocurrent generation and carrier diffusion were analyzed using metal patterns that allowed various areas of the thin films to be exposed to light. 

Keywords: $\beta$-Ga$_2$O$_3$, MOCVD, Crystal growth, Photocurrent

본 연구에서는 유기금속 화학 증착법 (metal-organic chemical vapor deposition, MOCVD)을 이용하여 서로 다른 온도에서 $\beta$-Ga$_2$O$_3$ 성장 후 박막 표면 형상 차이로부터 야기된 다이오드의 특성 변화에 대해 연구하였다. 주사 전자 현미경과 원자간력 현미경 분석 결과 MOCVD를 이용하여 각각 600 $^\circ$C와 900 $^\circ$C에서 성장된 시료는 표면 형상 및 거칠기에서 큰 차이를 보였으며 X-선 회절 분석 결과 900 $^\circ$C 성장 시료가 더 큰 다결정 특성을 가지는 것을 확인하였다. 각각의 박막에 Ti/Au 금속을 이용하여 제작한 쇼트키 다이오드로부터 분석된 전기적 특성 분석 결과, 표면이 평탄한 600 $^\circ$C 성장 시료에서 더 낮은 문턱 전압 및 암전류를 확인하여 표면 평탄도가 다이오드의 전기적 특성에 큰 영향을 주는 것을 확인할 수 있었다. 또한, 금속 패턴 형성을 통해 박막 노출 면적을 다양화하여 광 노출 면적에 따른 광전류 생성과 캐리어 확산에 대한 관계를 규명하였다.  

Keywords: $\beta$-Ga$_2$O$_3$, 유기금속 화학 증착법, 결정성장, 광전류

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