Method to fabricate self-aligned isolation in gallium nitride devices and integrated circuits

摘要

A method for forming an enhancement mode GaN HFET device with an isolation area that is self-aligned to a contact opening or metal mask window. Advantageously, the method does not require a dedicated isolation mask and the associated process steps, thus reducing manufacturing costs. The method includes providing an EPI structure including a substrate, a buffer layer a GaN layer and a barrier layer. A dielectric layer is formed over the barrier layer and openings are formed in the dielectric layer for device contact openings and an isolation contact opening. A metal layer is then formed over the dielectric layer and a photoresist film is deposited above each of the device contact openings. The metal layer is then etched to form a metal mask window above the isolation contact opening and the barrier and GaN layer are etched at the portion that is exposed by the isolation contact opening in the dielectric layer.

主权项

1. A method of forming an integrated circuit having at least two transistor devices, the method comprising:
forming a buffer layer on a substrate; forming a GaN layer over the buffer layer; forming a barrier layer over the GaN layer; forming a dielectric layer over the barrier layer; forming at least one device contact opening in the dielectric layer for each of the at least two transistor devices and an isolation contact opening in the dielectric layer between the at least two transistor devices; forming a metal layer over the dielectric layer, the device contact openings and the isolation contact opening; forming a photoresist film above each of the device contact openings, the photoresist film defining a metal mask window; etching the metal layer and, as part of the same metal layer etching step, etching a portion of the barrier layer and the GaN layer to form an isolation region where the metal mask window and isolation contact opening overlap.