| 摘要 |
The present invention provides stable and reliable extremely high resistance polysilicon resistors for use as SRAM load elements, and methods for their fabrication. In an embodiment, a resistor element of a semiconductor device includes at least one polysilicon layer, and a silicon nitride layer deposited directly onto this polysilicon layer. The silicon nitride layer prevents contamination of the polysilicon layer during subsequent fabrication process steps. A method of fabricating a polysilicon resistor on a semiconductor substrate is also provided. The method includes the step of depositing a layer of polysilicon on the substrate, followed by depositing a layer of protective material over the polysilicon layer to form a protected polysilicon layer. After deposition of the protective layer, resistors are formed by implanting dopants into the polysilicon layer, and patterning through lithography, and etching the nitride and the polysilicon layer. The step of depositing a layer of protective material can include depositing a layer of silicon nitride. Dopants can be selected from a group consisting of boron, phosphorous, and arsenic, and can be implanted at dosage levels generally within a range of between zero and 5*1013 ions/cm2 and at energy levels generally within a range of between 35 KeV and 80 KeV.
|
