THRESHOLD VOLTAGE ADJUSTMENT IN METAL OXIDE SEMICONDUCTOR FIELD EFFECT TRANSISTOR WITH SILICON OXYNITRIDE POLYSILICON GATE STACK ON FULLY DEPLETED SILICON-ON-INSULATOR

摘要

A fully depleted silicon-on-insulator MOSFET transistor with reduced variation in threshold voltage. The substrate of the transistor is doped to form a ground plane below a buried oxide layer. A lightly doped channel is formed over the buried oxide layer. A gate dielectric of Silicon Oxynitride is formed over the channel, and a polysilicon gate is formed over the gate dielectric. The polysilicon gate is doped to have a work function not greater 4.2 electron volts for a p-type doped channel (for an n-channel MOSFET), and not less than 5.0 electron volts for an n-type doped channel (for a p-channel MOSFET). The thickness of the buried oxide layer and the channel need not be greater than 20 nanometers and 10 nanometers, respectively.

主权项

1. An apparatus comprising:
a silicon substrate; a doped ground plane formed in the silicon substrate; a buried oxide layer formed in the silicon substrate; a silicon channel formed on the buried oxide layer, the silicon channel doped p-type; a first source/drain region formed in the silicon channel; a second source/drain region formed in the silicon channel; a dielectric formed on the silicon channel; and a polysilicon gate formed on the dielectric, wherein the polysilicon gate has a work function not greater than 4.2 eV.