GaN HFET中的能带峰耗尽

Exhaustion of Peak Energy Band in GaN HFET

考虑强场峰和耗尽电势随栅压的变化后,使用新编的场效应管能带计算软件计算了GaN HFET在不同栅、漏电压下的场效应管能带和漂移及局域电子气密度,发现了强场峰中耗尽区内外漂移电子气的耗尽台阶和能带峰台阶以及耗尽区外的局域电子气峰。研究了不同栅、漏电压下的场效应管能带的耗尽过程,发现耗尽区接触能带峰后的巨大能带畸变。提出了能带峰耗尽的新概念。运用应力偏置后测试偏置下局域电子气势垒和非稳态异质结的变化及局域电子气行为确立了应力偏置中内沟道夹断和外沟道强场峰的关联。通过施加应力偏置后在测试偏置下的非稳态强场峰充电过程中两种电子气的不同输运行为解释了动态沟道电流中的快峰和慢峰,建立起基于场效应管能带理论的新的动态电流崩塌模型。

Considered the variations of peak electric field and exhaustion potential with gate voltage,the bands of field-effect transistor and the density of drifting electron gases and localized electron gases under different gate and drain voltages had been calculated by using the new compiled calculation software.It was found that there were exhaustion bench and bench of peak band of the drifting electron gases inside and outside the exhaustion region and the peak localized gases outside the exhaustion region.By investigating the exhaustion progress of bands of field-effect transistor under different gate and drain voltages,a large band distortion appeared after the exhaustion region contacting with the peak energy band was founded,and a new concept of exhaustion of peak energy band was proposed.Through the variations of localized electron gases potential and unstable heterojunction and the behaviors of localized electron gases under the test biases after the stress biases,the relationship between the punch-off behavior in the inner channel and the peak electric field in outer channel during the stress biasing process was established.The fast peaks and slow peaks in dynamical channel current under test biasing were explained successfully by the different transport behaviors of two sorts of electron gases during the charging process in unstable peak electric field after the stress biasing,from which a new current collapse model based on the band of field-effect transistor was proposed.