Abstract: 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 AlGaN/GaN HEMTs with an AlN 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 ΔEc prominently,which is beneficial for strengthening the quantum limitation of 2DEG and decreasing the probability of hot electron tunneling through the AlGaN barrier layer to the surface.Therefore,an AlN insert layer appears to inhibit current collapse.

Key words: AlN insert layer, HEMTs, current collapse effect, hot electron