Reducing MEMS stiction by introduction of a carbon barrier

摘要

A mechanism for reducing stiction in a MEMS device by decreasing an amount of carbon from TEOS-based silicon oxide films that can accumulate on polysilicon surfaces during fabrication is provided. A carbon barrier material film is deposited between one or more polysilicon layer in a MEMS device and the TEOS-based silicon oxide layer. This barrier material blocks diffusion of carbon into the polysilicon, thereby reducing accumulation of carbon on the polysilicon surfaces. By reducing the accumulation of carbon, the opportunity for stiction due to the presence of the carbon is similarly reduced.

主权项

1. A method for manufacturing a microelectromechanical systems (MEMS) device, the method comprising:
forming a first polysilicon layer over a substrate; forming a sacrificial layer over the first polysilicon layer, wherein the sacrificial layer comprises silicon oxide deposited using tetraethyl orthosilicate (TEOS) gas; forming a second polysilicon layer over the sacrificial layer; annealing the second polysilicon layer wherein said annealing comprises heating the first and second polysilicon layers and the sacrificial layer to a temperature sufficient to relieve stress in the second polysilicon layer; and forming a carbon barrier layer between the sacrificial layer and one or more of the first and second polysilicon layers, wherein
the carbon barrier layer prevents diffusion of carbon into an adjacent polysilicon layer from the sacrificial layer during said annealing, andsaid forming the carbon barrier layer further comprises
forming a first carbon barrier layer over and in contact with at least a portion of the first polysilicon layer, wherein the first carbon barrier layer is formed prior to said forming the sacrificial layer; andforming a second carbon barrier layer over and in contact with the sacrificial layer, wherein
the second carbon barrier layer is formed prior to said forming the second polysilicon layer, and at least a portion of the second polysilicon layer is formed in contact with the second carbon barrier layer.