GaN HFET的沟道夹断特性和强电场下的电流崩塌

从自洽求解二维泊松方程和薛定谔方程出发,研究了纵、横向电场作用下GaNHFET沟道中的电子态和夹断特性。建立了不同异质结构和电场梯度下的电荷控制模型;运用热电子隧穿电流崩塌模型解释了强场电流崩塌的实验结果;强调了沟道夹断特性对电流崩塌的影响;研究了背势垒异质结构、场板电极和挖槽等抑制电流崩塌的方案,提出利用挖槽独立设计内、外沟道异质结构抑制强场电流崩塌的新思路。

Pinch-Off Behavior of Channel in GaN HFET and Current Collapse at High Electric Field

From the self-consistent solution of 2-D Poisson equation and Schrdinger equation,the electron states and pinch-off behavior in quantum well channel of GaN HFET under longitudinal and transversal electric field were investigated.A charge controlling model for different hete-rostructures and electric field gradients was established.By using the hot electron tunneling mechanism of current collapse,some experimental results about current collapse under high electric field were explained.The effect of pinch-off characteristic on current collapse was emphasized.The back barrier heterostructure,field plate structure and recessed gate were studied to reduce the current collapse.A new approach to design independently inner and outer channel ta-king advantage of recessed gate technology was proposed.