Method of making polysilicon resistor having adjustable temperature coefficients
AssigneeDallas Semiconductor Corporation
InventorsVarun Singh, Tanmay Kumar, Thomas E. Harrington, III, Roy Austin Hensley, Allan T. Mitchell, Jack Gang Qian
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Abstract
A polysilicon resistor is formed using a late implant process. Low dopant concentrations on the order of 6×1019 to 3.75×1020 have shown good results. with a reduced post anneal temperature. Both the first and second order temperature coefficients (TC1 and TC2) can then be adjusted. Using electrical trimming resistors can be produced with highly linear temperature characteristics. By varying the geometries of the resistors, low trimming threshold current densities and voltages can be used to produce good results.
Claims6
A method of making a polysilicon resistor comprising the steps of:
- providing a substrate,
- depositing a polycrystalline layer on said substrate,
- aligning and exposing a poly protect mask,
- poly doping the polycrystalline layer, other than the resistor
- forming an insulating oxide,
- aligning and exposing the mask for the resistor,
- implanting the resistor
- depositing an inter level dielectric,
- annealing the inter level dielectric, and
- completing the processing using low temperature processing.
Dependencies are inferred from the claim text.