Normally off gallium nitride field effect transistors (fet)

Abstract

A heterostructure field effect transistor (HFET) gallium nitride (GaN) semiconductor power device comprises a hetero-junction structure comprises a first semiconductor layer interfacing a second semiconductor layer of two different band gaps thus generating an interface layer as a two-dimensional electron gas (2DEG) layer. The power device further comprises a source electrode and a drain electrode disposed on two opposite sides of a gate electrode disposed on top of the hetero-junction structure for controlling a current flow between the source and drain electrodes in the 2DEG layer. The power device further includes a floating gate located between the gate electrode and hetero-junction structure, wherein the gate electrode is insulated from the floating gate with an insulation layer and wherein the floating gate is disposed above and padded with a thin insulation layer from the hetero-junction structure and wherein the floating gate is charged for continuously applying a voltage to the 2DEG layer to pinch off the current flowing in the 2DEG layer between the source and drain electrodes whereby the HFET semiconductor power device is a normally off device.

Description

technical field [0001] The invention mainly relates to a structure and a preparation method of a semiconductor power device. More precisely, the present invention relates to a gallium nitride (GaN)-based field effect transistor manufactured with a novel device structure and fabrication method, and the normally-off GaN-based field effect transistor has extremely high performance when conducting a large current. low on-resistance. Background technique [0002] Conventional methods of configuring and fabricating Gallium Nitride (GaN) based Field Effect Transistors (FETs) are still challenged by the technical problem of providing normally off FET transistors with facile fabrication and operational configurations. More specifically, Gallium Nitride (GaN) based FETs are configured to fabricate High Electron Mobility Transistors (HEMTs). For power transistor devices, this type of transistor can replace some of the now common and widely used silicon-based semiconductor power devic...

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Problems solved by technology

However, such devices suffer from low inversion mobility and high electric fields in the oxide when the device is biased to break down, causing device reliability issues

To solve this problem, we increase the thickness of the oxide layer, but this reduces the transconductance and leads to an unnecessarily high RdsA

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