Analysis of the leakage current in GaN-based heterostructure buffer layer

作者：Zhang Jin Cheng^*; Dong Zuo Dian; Qin Xue Xue; Zheng Peng Tian; Liu Lin Jie; Hao Yue

来源：Acta Physica Sinica, 2009, 58(3): 1959-1965.

• AlGaN/GaN heterostructure
• GaN buffer layer
• leakage current
• nucleation layer

The relations between the buffer leakage current and the characteristics of nucleation layer of AlGaN/GaN heterostructure have been obtained by comparative study of depletion capacitance of C-V characteristics in GaN-based heterostructure. The results showed that, the heterostructure material based on a sapphire substrate with a low-temperature GaN nucleation layer and SiC substrate with a high-temperature AIN nucleation layer have smaller buffer leakage current and lower carrier concentration of the background GaN buffer layer than that based on a sapphire substrate with a low-temperature AIN nucleation layer. A thorough analysis shows that, there is an n-type GaN conductive layer near the GaN/substrate interface in buffer layer based on the thinner nucleation layers. Contrarily, high resistivity GaN buffer layers appear in heterostructure materials based on thicker nucleation layer. One of the main causes of device leakage is the n-type GaN conductive layer. Appropriately improving the quality and thickness of nucleation layer can effectively reduce the carrier concentration, raise the resistivity and suppress the leakage current of the GaN buffer layer.

• 出版日期2009-3
• 单位西安电子科技大学