Field effect power transistors

摘要

A normally OFF field effect transistor (FET) having a plurality of contiguous nitride semiconductor layers having different composition and heterojunction interfaces, wherein when there is no potential difference between a first gate and a common ground voltage, a two dimensional electron gas (2DEG) is present at a plurality of heterojunctions in each of a source access region and a drain access region, and substantially no 2DEG is present adjacent any regions of the heterojunctions under the first gate.

主权项

1. A normally OFF field effect transistor (FET) comprising:
a plurality of contiguous nitride semiconductor layers having different composition and heterojunction interfaces between contiguous layers, a Fermi level, and conduction and valence energy bands; a source and a drain overlying a top nitride layer of the plurality of nitride layers and having source and drain access regions respectively comprising regions of at least two of the heterojunctions near the source and drain; a first gate between the source and drain; and a set of nitride layers comprising:
a first nitride layer having a first band gap;a second nitride layer contiguous with the first layer and having a second band gap wider than the first band gap and an electrostatic field having a direction that operates to cause electrons in the second layer to drift towards the heterojunction between the first and second layers;a third nitride layer having a third band gap and an electrostatic field in a direction opposite to the electric field in the second layer that operates to prevent accumulation of electrons at the heterojunction between the first and second layers; wherein when there is no potential difference between the first gate and a common ground voltage, a two dimensional electron gas (2DEG) is present at a plurality of heterojunctions in each of the source and drain access regions, and substantially no 2DEG is present adjacent any regions of the heterojunctions under the first gate.