Fabrication method for a deep trench isolation structure of a high-voltage device
AssigneeVanguard International Semiconductor Corporation
InventorsJia-Wei Yang, Chih-Cherng Liao
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Abstract
A fabrication method for a semiconductor device. On a semiconductor silicon substrate with a first type conductivity, an epitaxial layer with a second type conductivity and an oxide layer on the epitaxial layer are formed with at least a deep trench. Ion implantation is used to form an ion diffusion region with the first type conductivity which is formed in the epitaxial layer and surrounds the sidewall and bottom of the deep trench. An oxide liner is formed on the sidewall and bottom of the deep trench, and then an undoped polysilicon layer is formed to fill the deep trench. The combination of the ion diffusion region and the undoped polysilicon layer serves as a deep trench isolation structure.
Claims21
A fabrication method for a semiconductor device, comprising the steps of:
- providing a semiconductor silicon substrate with a first type conductivity;
- forming an epitaxial layer with a second type conductivity overlying the semiconductor silicon substrate;
- forming an oxide layer overlying the epitaxial layer;
- forming at least one deep trench which passes through the oxide layer and the epitaxial layer;
- forming an ion diffusion region with the first type conductivity in the epitaxial layer, wherein the ion diffusion region surrounds the sidewall and bottom of the deep trench;
- forming an oxide liner on the sidewall and bottom of the deep trench;
- and
- forming an undoped polysilicon layer in the deep trench;
- wherein, the combination of the ion diffusion region and the undoped polysilicon layer within the deep trench serves as a deep trench isolation structure.
A fabrication method for a high-voltage device, comprising the steps of:
- providing a semiconductor silicon substrate with a first type conductivity;
- forming an epitaxial layer with a second type conductivity overlying the semiconductor silicon substrate;
- forming an oxide layer overlying the epitaxial layer;
- forming at least two deep trenches which pass through the oxide layer and the epitaxial layer, wherein the two deep trenches define a high-voltage area;
- forming an ion diffusion region with the first type conductivity in the epitaxial layer, wherein the ion diffusion region surrounds the sidewall and bottom of each deep trench;
- forming an oxide liner on the sidewall and bottom of each deep trench;
- and
- forming an undoped polysilicon layer in each deep trench;
- wherein, the combination of the ion diffusion region and the undoped polysilicon layer within each deep trench serves as a deep trench isolation structure.
Dependencies are inferred from the claim text.