Patent ID: 6736982
Filing Date: 2004-05-18
Classification: B81B,B81C,G01C,G01P

Abstract:
A method for fabricating a micromachined vertical vibrating gyroscope comprising steps ofa) providing a lightly doped single crystal silicon substrate; b) forming a heavily doped buried layer in the substrate; c) forming an insulating ring on the surface of the substrate; d) performing selective epitaxial growth to form a vertical epitaxial single crystal silicon layer on the exposed silicon surface of the substrate and a lateral overgrowth single crystal silicon layer on the insulating ring; e) conducting first deep reactive ion etching to form first trenches in the vertical epitaxial layer; f) filling up the first trenches with an insulating material(s); g) conducting second deep reactive ion etching to form second trenches in the vertical epitaxial layer; h) performing anodization to convert the buried layer into a porous silicon layer; i) removing a portion of the porous silicon layer to form suspension structures; j) conducting pre-deposition with a diffusion source; k) conducting post-diffusion in oxygen atmosphere to form a heavily doped single crystal silicon layer on the surfaces of the suspension structures and turn the rest of the porous silicon layer into an oxidized porous silicon layer; l) performing low pressure chemical vapor deposition to form an insulating layer on the surfaces of the suspension structures; and m) depositing a metal layer on the top surfaces and sidewalls of the suspension structures.