Open AccessAnalysis of the leakage current in GaN-based heterostructure buffer layer
Author(s) -
Jincheng Zhang,
Dong Zuo-Dian,
Qin Xue-Xue,
Zheng Peng-Tian,
Linjie Liu,
Yue Hao
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.1959
Subject(s) - materials science , heterojunction , nucleation , optoelectronics , layer (electronics) , buffer (optical fiber) , leakage (economics) , sapphire , substrate (aquarium) , barrier layer , composite material , optics , chemistry , electrical engineering , laser , oceanography , organic chemistry , geology , engineering , physics , economics , macroeconomics
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 AlN 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 AlN 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.