Diffusion barrier layer for mems devices

Abstract

Described herein is the use of a diffusion barrier layer between metallic layers in MEMS devices. The diffusion barrier layer prevents mixing of the two metals, which can alter desired physical characteristics and complicate processing. In one example, the diffusion barrier layer may be used as part of a movable reflective structure in interferometric modulators.

1 . A method of manufacturing an interferometric modulator, comprising:
 depositing a silicon layer;   depositing a diffusion barrier layer onto the silicon layer;   depositing a metallic layer comprising a metal onto the diffusion barrier layer, wherein the diffusion barrier layer is adapted to substantially inhibit any portion of the silicon layer from mixing with any portion of the metallic layer; and   etching the silicon layer using an etchant capable of etching the silicon but not an alloy of silicon and the metal.   
     
     
         2 . The method of  claim 1 , wherein the diffusion barrier layer comprises an oxide, nitride, or carbide. 
     
     
         3 . The method of  claim 1 , wherein the diffusion barrier layer comprises silicon dioxide. 
     
     
         4 . The method of  claim 1 , wherein the metal includes aluminum. 
     
     
         5 . The method of  claim 1 , wherein the silicon layer includes amorphous silicon. 
     
     
         6 . The method of  claim 1 , wherein the etchant comprises XeF 2 . 
     
     
         7 . An interferometric modulator produced by the process of  claim 1 .