Reduction of buffer‐related current collapse in GaN FETs under favour of a field plate

Abstract

AbstractTwo‐dimensional transient analysis of GaN MESFETs with a semi‐insulating buffer layer is performed in which a deep donor and a deep acceptor are considered in the buffer layer, and the results are compared between the two cases with and without a field plate. It is shown that buffer‐related drain lag is reduced by introducing a field plate because trapping effects become smaller. It is also shown that current collapse and gate lag are also reduced in the field‐plate structure. The dependence on SiN passivation layer thickness is also studied, indicating that there is an optimum SiN thickness to minimize the buffer‐related current collapse and drain lag in GaN‐based FETs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)