AlN插入层与AlGaN/GaN HEMT电流崩塌效应的关系

Correlations Between an AlN Insert Layer and Current Collapse in AlGaN/GaN HEMTs

比较有无AlN插入层AlGaN/GaNHEMTs在直流偏置应力条件下的电流崩塌程度,研究AlN插入层对电流崩塌的影响.从测试结果看,无AlN插入层的AlGaN/GaNHEMTs有更显著的电流崩塌程度,表明AlN插入层对电流崩塌效应有显著的抑制作用.模拟的AlGaN/GaN能带结构表明,AlN插入层能显著提高AlGaN导带底能级,增加异质结的带隙差.带隙差的增加有利于减小电子遂穿几率,加强沟道二维电子气的量子限制,从而抑制电流崩塌效应.

Based on a comparison of the degree of drain current collapse in AlGaN/GaN HEMTs with and without an AlN insert layer under short-term DC bias stress, the effects of an AlN insert layer on current collapse induced by DC bias stress are investigated. Under some DC bias stress, the degree of drain current collapse of AIGaN/GaN HEMTs with an AIN insert layer is less prominent than that with no AlN insert layer, indicating that an AlN insert layer can inhibit current collapse effectively. The energy band structures of AlGaN/GaN HEMTs with and without AlN insert layers make clear that an AlN insert layer raises the conductance band and increases the effective heterostructure band discontinuity △Ec prominently, which is beneficial for strengthening the quantum limitation of 2DEG and decreasing the probability of hot electron tunneling through the AIGaN barrier layer to the surface. Therefore, an AlN insert layer appears to inhibit current collapse.