Trade-off between thickness and temperature ramping rate of GaN buffer layer studied for high quality GaN growth on GaAs (111)A substrate

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• 作者：Murakami ; Hisashi ; Kangawa ; Yoshihiro ; Kumagai ; Yoshinao ; Koukitu ; Akinori
• 关键词：81.05.Ea ; 81.10.Bk ; 81.15.Kk ; 68.55.Jk ; A1. Crystal structure ; A3. Vapor phase epitaxy ; B1. Nitrides ; B2. Semiconducting III&ndash ; V materials
• 刊名：Journal of Crystal Growth
• 出版年：2004
• 期刊代码：49_00220248
• 类别：ch
• 出版时间：July 15, 2004
• 卷：268
• 期：1-2
• 页码：1-7
• 文件大小：331 K

摘要

The correlation between crystallization of low-temperature (LT) GaN buffer layer and crystalline quality of subsequently grown thick GaN layer at high-temperature on GaAs (111)A substrate has been investigated. During heating of LT-GaN buffer layer to 1000°C, the degree of crystallization highly depended on the thickness and the temperature ramping rate of GaN buffer layers. When the LT-GaN buffer layer was less than 40-nm-thick or temperature ramping rate was low, excess crystallization and/or agglomeration of the buffer layer occurred, which resulted in a poor crystalline quality of the GaN epitaxial layer subsequently grown on it. On the other hand, when the thickness of LT-GaN buffer layer exceeded 100nm, there was relatively little agglomeration of buffer layer, which also resulted in poor crystalline quality of the subsequently grown GaN. To grow high-quality GaN layer at high-temperature, optimum crystallization condition for GaN buffer layer just prior to high-temperature growth was found to be as follows: single crystallites region in the GaN buffer layer occupied a volume 40%as large as the randomly aligned matrix. The trade-off between thickness and temperature ramping rate of GaN buffer layer clearly indicates that the degree of crystallization of the GaN buffer layer is an important parameter for achieving high-quality GaN growth at high-temperature.