Patent ID: 6531331
Filing Date: 2003-03-11
Classification: B81C

Abstract:
A method for integrating a metal-oxide semiconductor field effect transistor (MOSFET) with a microelectromechanical systems (MEMS) device on a semiconductor substrate, comprising:forming a gate insulator of the MOSFET on an electronics portion of the substrate surface; forming a gate electrode of the MOSFET on the gate insulator; forming an inter-layer dielectric on the electronics portion of the substrate, thereby encapsulating the gate electrode and the gate insulator; forming a gate electrical contact through the inter-layer dielectric to the gate electrode; forming a source electrical contact through the inter-layer dielectric to a source region of the substrate proximate to one side of the gate electrode wherein the source electrical contact further comprises a solid dopant source; forming a drain electrical contact through the inter-layer dielectric to a drain region of the substrate proximate to the other side of the gate electrode wherein the drain electrical contact further comprises a solid dopant source; forming a MEMS device structure on a MEMS portion of the substrate surface comprising at least one dielectric layer on the substrate, at least one structural layer built up from the at least one dielectric layer, and at least one sacrificial layer interleaving the at least one structural layer; heating the substrate to a sufficiently high temperature to thermally diffuse dopant atoms from the source and drain electrical contacts into the substrate to form the source and drain of the MOSFET and to relieve the stress in the at least one structural layer of the MEMS device structure; forming electrical interconnections from the gate electrical contact, the source electrical contact, and the drain electrical contact of the MOSFET to the MEMS device structure; and removing the at least one sacrificial layer to release the MEMS device.