Gallium nitride devices having low ohmic contact resistance

US8772786B2 · kind B2 · utility

Assignee

• Raytheon Company · US

Inventors

• Kamal Tabatabaie · Sharon, US
• William E. Hoke · Wayland, US
• Eduardo M. Chumbes · Andover, US
• Kevin Robert McCarthy · Park City, US

Key dates

• Filing date: Jul 13, 2012
• Grant date: Jul 8, 2014
• Expiry date: Jul 13, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/8503

Abstract

A semiconductor structure having mesa structure comprising: a lower semiconductor layer; an upper semiconductor layer having a higher band gap than, and in direct contact with, the lower semiconductor layer to form a two-dimension electron gas (2DEG) region between the upper semiconductor layer. The 2DEG region has outer edges terminating at sidewalls of the mesa. An additional electron donor layer has a band gap higher than the band gap of the lower layer disposed on sidewall portions of the mesa structure and on the region of the 2DEG region terminating at sidewalls of the mesa. An ohmic contact material is disposed on the electron donor layer. In effect, a sideway HEMT is formed with the electron donor layer, the 2DEG region and the ohmic contact material increasing the concentration of electrons (i.e., lowering ohmic contact résistance) all along the contact between the lower semiconductor layer and the electron donor layer.