Enhancement mode III-nitride device and method for manufacturing thereof

A method of manufacturing an enhancement mode III-nitride high electron mobility transistor (HEMT), the method comprising:

• providing a substrate comprising a stack of III-nitride layers on the substrate, each layer comprising a III-nitride material, and a passivation layer comprising high temperature (HT) silicon nitride overlying and in contact with an upper layer of the stack of III-nitride layers, wherein the HT silicon nitride is formed by metal-organic chemical vapor deposition (MOCVD) or low pressure chemical vapor deposition (LPCVD) at a temperature higher than about 450° C., wherein the passivation layer is formed in-situ with the stack of III-nitride layers;
• forming a recessed gate region by removing substantially completely the passivation layer only from a gate region, thereby exposing the underlying upper layer,
• forming a p-doped GaN layer at least in the recessed gate region, thereby filling at least partially the recessed gate region;
• and
• forming a gate contact in the gate region and source/drain contacts through the passivation layer.