Investigation of flat band voltage shift in recessed-gate GaN MOSHFETs with post-metallization-annealing in oxygen atmosphere
Investigation of flat band voltage shift in recessed-gate GaN MOSHFETs with post-metallization-annealing in oxygen atmosphere
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DOI：
10.1088/0268-1242/30/11/115008
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发表时间：
2015-10
影响因子：
1.9
通讯作者：
Jae-Gil Lee;Hyun-Seop Kim;Jung-Yeon Lee;K. Seo;H. Cha
中科院分区：
文献类型：
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作者：
Jae-Gil Lee;Hyun-Seop Kim;Jung-Yeon Lee;K. Seo;H. Cha
研究了氧气氛下后金属化-退火(PMA)对凹栅GaN金属氧化物半导体异质结场效应晶体管(MOSHFET)的影响。MOS的平带电压是氧化物中体电荷和界面电荷的函数，它强烈地依赖于后退火工艺和沉积条件。通过O2 PMA工艺，GaN MOSHFET采用了ICPCVD SiO_2栅氧化层和Ni/Au金属栅，实现了阈值电压的正漂移，从而实现了正常关断操作。根据X射线能谱和X射线光电子能谱的分析表明，SiO_2/GaN界面质量的改善和类金属Ga能级的提高是阈值电压正移的主要原因。
We have investigated the effects of post-metallization-annealing (PMA) in oxygen atmosphere on recessed-gate GaN metal-oxide-semiconductor heterostructure field effect transistors (MOSHFETs). The flat band voltage of MOS is a function of bulk and interface charges in the oxide, which strongly depends on a post-annealing process as well as deposition conditions. A positive threshold voltage shift enabling normally-off operation has been achieved by an O2 PMA process where the GaN MOSHFET employed an ICPCVD SiO2 gate oxide with a Ni/Au metal gate. According to the analysis using energy dispersive x-ray spectroscopy in transmission electron microscopy and x-ray photoelectron spectroscopy, it is suggested that the improved SiO2/GaN interface quality with an enhanced metallic-like Ga level was responsible for the positive shift in threshold voltage.