HVPE에 의해 성장된 AlGaN epi layer의 특성
The properties of AlGaN epi layer grown by HVPE
0
조회
0
다운로드
7
인용
0
참고문헌
초록
AlGaN는 3.4~6.2 eV까지 넓은 밴드갭을 가지는 직접천이형 반도체이다. 최근에 자외영역의 광소자가 다양하게응용되면서 자외선 발광이 가능한 AlGaN 역시 주목받고 있다. 이를 위해서는 고품질의 AlGaN 층이 필요하지만 GaN 층위에 AlGaN 층을 성장하는 것은 이들의 격자상수와 열팽창계수 차이로 인해 어렵다. 본 논문에서, multi-sliding boat법이적용된 혼합소스 HVPE법을 이용하여 GaN template 위에 LED 구조를 성장하였다. 활성층의 Al 조성을 조절함으로써AlGaN의 격자상수 변화와 광학적 변화를 관찰하고자 하였다. 에피 성장을 위해 HCl과 NH3 가스를 혼합소스 표면으로 흘려주었고, 수송가스로는 N2를 사용하였다. 소스영역과 성장영역의 온도는 각각 900과 1090oC로 안정화하였다. 성장 후 샘플은 x-ray diffraction(XRD)과 electro luminescence(EL) 측정을 하였다
Abstract
The AlGaN layer has direct wide bandgaps ranging from 3.4 to 6.2 eV. Nowadays, it is becoming more important to fabricate optical devices in an UV region for the many applications. The high quality AlGaN layer is necessary to establish the UV optical devices. However, the growth of AlGaN layer on GaN layer is difficult due to the lattice mismatch and difference thermal expansion coefficient between GaN layer and AlGaN layer. In this paper, we attempted to grow the LED structure on GaN template by mixed-source HVPE method with multi-sliding boat system. We tried to find the optical and lattice transition of active layer by control the Al content in mixed-source. For the growth of epi layer, the HCl and NH3 gas were flowed over the mixed-source and the carrier gas was N2. The temperature of source zone and growth zone was stabled at 900 and 1090oC, respectively. After the growth, we performed the x-ray diffraction (XRD) and electro luminescence (EL) measurement.
참고문헌 (10)
- Motoaki Iwaya, "Suppression of phase separation of AlGaN during lateral growth and fabrication of high-efficiency UV-LED on optimized AlGaN", Journal of Crystal Growth, 237, pp.951~955 (2002)
- A.A. Allerman, "Growth and design of deep-UV (240~290 nm) light emitting diodes using AlGaN alloys", Journal of Crystal Growth, 272, pp.227~ (2004)
- I.-S. Seo, "The role of AlN buffer layer in AlxGa1−.xN", GaN heterostructures with x from 0.35 to 0.5 grown on sapphire (0 0 0 1), 2002, pp.241, 297~
- T. Namazu, "Characterization of single crystal silicon and electroplated nickel films by uniaxial tensile test with in situ X-ray diffraction measurement", Fatigue Fract. Engng. Mater. Struct, 30, pp.13~ (2007)
- A. Krost, "Nearly strain-free AlGaN on (0 0 0 1) sapphire: X-ray measurements and a new crystallographic growth model", Journal of Crystal Grwoth, 221, pp.251~ (2000)
- A. SH. Hussein, "Effect of Al mole fraction on structural and electrical properties of AlxGa1 −. xN", GaN heterostructures grown by plasma-assisted molecular beam epitaxy, 2011, pp.257, 4159~
- H. Ashraf, "Thick GaN layers grown by HVPE: Influence of the templates", Journal of Crystal Growth, 310, pp.3957~ (2008)
- B. L⁄. ucznik, "Deposition of thickGaN layers by HVPE on the pressure grown GaN substrates", Journal of Crystal Growth, 281, pp.38~ (2005)
- Yamina Andre, "Low dislocation density high-quality thick hydride vapour phase epitaxy (HVPE) GaN layers", Journal of Crystal Growth, 306, pp.86~ (2007)
- S.T. Kim, "Preparation and properties of free-standing HVPE grown GaN substrates", Journal of Crystal Growth, 194, pp.37~ (1998)