Effects of Si-doping on structural and electrical characteristics of polar, semi-polar, and non-polar AlGaN epi-layers

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• 作者：Yi Wang ; Xiong Zhang ; ^{xzhang62@aliyun.com" class="auth_mail" title="E-mail the corresponding author} ; Huakai Luan ; Hongquan Yang ; Shuchang Wang ; Qian Dai ; Zili Wu ; Yiping Cui
• 关键词：AlGaN ; Si-doping ; Structural properties ; Electrical properties ; Metal&ndash ; organic chemical vapor deposition
• 刊名：Materials Science in Semiconductor Processing
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：42
• 期：part_P3
• 页码：344-348
• 全文大小：2349 K

文摘

The effects of Si-doping on the structural and electrical properties of the wurtzite AlGaN epi-layers grown on polar, semi-polar, and non-polar sapphire substrates by metal organic chemical vapor deposition (MOCVD) were studied with X-ray diffraction, scanning electron microscopy, and hall effect measurement. The characterization results showed that both the surface morphology and the crystal quality of the polar AlGaN samples grown on a-plane sapphire substrates was improved with increasing Si concentration due to the Si-induced increase in dislocation movement. It was also found that the folds on the surfaces of the semi-polar and non-polar AlGaN samples grown on m- and r-plane sapphire substrates, respectively were significantly reduced in consequence of the growth suppression along c direction by Si-doping. Moreover, owing to the enhanced crystal quality, an increase in both the mobility and the carrier density for the polar AlGaN samples grown on a-plane sapphire substrates was achieved as the Si-doping level was increased. In addition, a relatively high electron concentration was obtained from the undoped semi-polar AlGaN samples grown on m-plane sapphire substrate, which is helpful to fabricate high quality semi-polar AlGaN-based ultra-violet light emitting diodes (UV-LEDs).