Analysis of Breakdown Characteristics of AlGaN/GaN HEMTs with Double Passivation Layers

Two-dimensional analysis of off-state drain current-drain voltage characteristics in AlGaN/GaN high electron mobility transistors is performed; where two cases with a single passivation layer (SiN) and double passivation layers (thin SiN and high-k dielectric) are compared. It is shown that in the case of double passivation layers, the breakdown voltage is enhanced significantly when comparing at the same insulator thickness. This is because in this case the electric field around the drain edge of gate is weakened. Also, in the case of double passivation layers, the breakdown voltage is shown to become higher when the relative permittivity of the second passivation layer becomes higher.