(Digital Presentation) Analysis of MIS-HEMT Kink Effect in Saturation Region

Abstract

In this work, the Metal-Insulator-Semiconductor High Electron Mobility Transistor (MIS-HEMT) behavior in saturation region was analyzed and compared with a GaN MOSFET. The MIS-HEMT presents a current level about 30 times higher than GaN MOSFET, for the same bias conditions. The different saturation points (VDS sat) of the MOS and HEMT conductions is responsible for the appearance of a kink in the drain current (IDS) current as a function of drain voltage (VDS) curve. The output conductance (gD) of the MOSFET presented a strong dependence on VGT, while the MIS-HEMT only a slightly dependence was observed. The MIS-HEMT kink effect (MH kink) was defined by the drain voltage where the bump occurs. The MH kink only occurs for a high enough gate bias to enable the MOS conduction, and MH kink value increases with the gate voltage overdrive (VGT) and its variation tends to saturate for VGT higher than 3,5V.