Modulation of gate polysilicon doping profile by sidewall implantation
AssigneeAdvanced Micro Devices, Inc.
InventorAsim Selcuk
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Abstract
A device and method to modulate a gate polysilicon doping profile by performing a sidewall implantation. The method includes forming a gate on a substrate and implanting ions through a sidewall in the gate. The ion implantation is performed by projecting the ions at an angle that is not perpendicular to the top surface of substrate and in a direction that is towards the surface of sidewall. The ion implantation process can be performed using a type of dopant that either increases or decreases the net dopant concentration in a gate polysilicon layer in a region of the gate adjacent the sidewall and adjacent a gate oxide layer.
Claims5
A method for modulating a gate polysilicon doping profile of a metal-oxide semiconductor field effect transistor, said method comprising the steps of:
- forming a gate on a substrate, the gate having a gate oxide layer formed on the substrate and an etched polysilicon layer formed on the gate oxide layer, the polysilicon layer having a top surface and opposed sidewalls;
- forming a photoresist mask on a first portion of the top surface of the polysilicon layer and to entirely cover one sidewall, the entire other sidewall and a second portion of the top surface, less than the first portion, being exposed;
- and
- performing an angled ion implantation on the exposed sidewall and the exposed portion of the top surface of the polysilicon layer such that a doping profile of a region in the polysilicon layer adjacent the exposed sidewall and adjacent the gate oxide layer is unequal to a doping profile of a remainder of the polysilicon layer of the gate.
Dependencies are inferred from the claim text.