Effects of the V/III ratio on a-plane GaN epitaxial layer on r-plane sapphire grown by HVPE
r-Plane sapphire 위에 HVPE에 의해 성장한 a-plane GaN에피텍셜층의 V/III족 ratio에 따른 특성 변화

Ju-Hyung Ha, Mi-Seon Park, Won-Jae Lee, Young-Jun Choi, Hae-Yong Lee
2014 Journal of the Korean Crystal Growth and Crystal Technology  
In this study, effects of the V/III ratio on a-plane GaN epitaxial on r-plane grown by HVPE have been investigated. According to increasing of V/III ratio, the value of FWHM of a-plane (11-20) GaN and the value of surface roughness (Ra) were decreased. Growth rate of a-plane GaN epitaxial layer were increased until V/III ratio = 7 as the increasing of V/III ratio, but it was reduced at V/III ratio = 10. At V/III ratio = 10, the FWHM of a-plane (11-20) GaN RC and the surface roughness (Ra) were
more » ... oughness (Ra) were 829 arcsec and 1.58 nm, respectively, as the lowest value in this study. Also for V/III ratio = 10, cracks under surface or voids were observed the lowest values in images of optical microscope. An M-shaped azimuthal dependence over 360 o angle range was observed for all samples. At V/III ratio = 10, the difference of FWHM of a-plane GaN between 0 o and 90 o was 439 arcsec revealed as the lowest value in the 4 samples. Key words a-plane GaN, r-plane sapphire, HVPE, Omega scan, AFM 1. 서 론 GaN와 InN, AlN들은 최근에 많은 관심 속에서 가시 영역과 자외선영역에서 LED 분야로 성공적인 개발이 이루어 져왔다[1]. 이는 0.7 eV(InN)에서 6.2 eV(AlN)에 이르는 넓은 밴드구조를 가지며 자외선에서 적외선 영역 까지 폭 넓은 발광대역의 조절이 가능할 뿐만 아니라 고 온 및 고출력 하에서 안정된 동작이 가능하여 현재 LED(Light Emitting Diode)외에 LD(Laser Diode)와 고 주파 장비들에서도 개발이 되고 있다[2, 3]. 가시광선영역에서의 기술적인 문제점이 있는데 파장이 길어질수록 외부 양자효율이 급격하게 떨어진다는 점이 †
doi:10.6111/jkcgct.2014.24.3.089 fatcat:weum4amqx5flhcu6hc3jxljl2u