Patent ID: 11935795
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 12:
13. A method for forming a semiconductor device, comprising:
depositing a protective coating on a first polysilicon layer in a first transistor, wherein the protection coating further comprises a first dielectric layer;
forming an epitaxial layer on the protective coating for a second transistor; and
depositing a second polysilicon layer over the epitaxial layer,
wherein the protective coating comprises a third polysilicon layer, wherein the third polysilicon layer is deposited at a first temperature in a range of 600-700 degree Celsius, and wherein the third polysilicon layer in the protective coating is configured to protect the first polysilicon layer when the second polysilicon layer is etched,
wherein the first polysilicon layer is deposited at the first temperature, and
wherein the second polysilicon layer is deposited at a second temperature in a range of 540 and 560 degree Celsius.