The development and device applications of the InGaAlN system have progressed dramatically with improvements in crystalline quality by achieved through a buffer layer, the realization of p-type doping, and the growth of ternary alloys. As a substrate, sapphire is mainly used for epitaxial growth because of the lack of a GaN bulk crystal. However, many cracks in GaN film can still be observed and its X-ray rocking curve width is less than 100 arc seconds. This is are thought to be due to the lattice constants and thermal expansion coefficients of GaN and sapphire differ by 13.8% and by -34.2%, respectively. These values are extremely large in comparison with the corresponding values for InP and GaAs. Lattice-matching growth thus remains a basic problem in growing the high-quality epitaxial films necessary for high-performance devices. This paper reviews attempts at lattice-matching growth. Lattice-matching growth of InGaN on a house-made ZnO substrate and near-lattice-matching growth of GaN on SiC and NdGaO3 substrates have been proposed and performed, and the effects of lattice-matching have been confirmed. Various types of surface planes commercially available sapphire substrates are also discussed.
|ジャーナル||Materials Research Society Symposium - Proceedings|
|出版物ステータス||Published - 1996 1 1|
|イベント||Proceedings of the 1995 MRS Fall Meeting - Boston, MA, USA|
継続期間: 1995 11 26 → 1995 12 1
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials