Method for forming a silicon membrane with controlled stress
First Claim
Patent Images
1. A method for fabricating a silicon membrane with a desired characteristic and level of internal stress comprising the steps of:
- (a) selecting a silicon substrate with a first electrical conductivity characteristic, said substrate having first and second opposite sides;
(b) selecting a dopant according to the desired characteristic of internal stress, said dopant having a second electrical conductivity characteristic of opposite polarity to said first electrical conductivity characteristic;
(c) forming a doped layer of predetermined thickness adjacent to said first surface of said substrate wherein the concentration of said dopant is selectively controlled to provide the desired level of internal stress in said doped layer;
(d) electrochemically etching a portion of said second surface of said substrate to a boundary of said doped layer, thereby forming a stress controlled membrane having a thickness approximately equal to the thickness of said doped layer.
2 Assignments
0 Petitions
Accused Products
Abstract
A method for fabricating a silicon membrane with predetermined stress characteristics. A silicon substrate is doped to create a doped layer as thick as the desired thickness of the membrane. Stress within the doped layer is controlled by selecting the dopant based on its atomic diameter relative to silicon and controlling both the total concentration and concentration profile of the dopant. The membrane is then formed by electrochemically etching away the substrate beneath the doped layer.
67 Citations
15 Claims
-
1. A method for fabricating a silicon membrane with a desired characteristic and level of internal stress comprising the steps of:
-
(a) selecting a silicon substrate with a first electrical conductivity characteristic, said substrate having first and second opposite sides; (b) selecting a dopant according to the desired characteristic of internal stress, said dopant having a second electrical conductivity characteristic of opposite polarity to said first electrical conductivity characteristic; (c) forming a doped layer of predetermined thickness adjacent to said first surface of said substrate wherein the concentration of said dopant is selectively controlled to provide the desired level of internal stress in said doped layer; (d) electrochemically etching a portion of said second surface of said substrate to a boundary of said doped layer, thereby forming a stress controlled membrane having a thickness approximately equal to the thickness of said doped layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
Specification