US 6,087,208 A · Method for increasing gate capacitance by using both high and low dielectric gate material

Abstract

A method for fabricating a MOSFET device is provided. The method includes a step of fining a gate oxide including first and second gate oxide materials. The first gate oxide material has a higher dielectric constant than the second gate oxide material. The first gate oxide material is formed to be over source/drain extension regions of the device; and the second gate oxide material is formed over a channel region of the device. The first gate oxide material has a low dielectric constant and provides for mitigating gate fringing field effects. The second gate oxide material has a high dielectric constant and provides for forming a thick gate oxide over a channel region of the device. Controlled uniform growth of the second gate oxide material is facilitated because of the thickness thereof.

Claims9

Dependent claims

A method for fabricating a MOSFET device including the step of:

forming a gate oxide including first and second gate oxide materials, the first gate oxide material having a dielectric constant of about .epsilon.<100 and the second gate oxide material having a dielectric constant of about .epsilon.>100 and a higher dielectric constant than the first gate oxide, the step of forming the gate oxide including the steps of:
forming the first gate oxide material over source/drain extension regions of the device;
etching a portion of the first gate oxide material between the source/drain extension regions of the device;
and
replacing said etched portion by forming the second gate oxide material over a channel region of the device.

2 more elements

Dependencies are inferred from the claim text.

Method for increasing gate capacitance by using both high and low dielectric gate material

Life of this patent

Method for increasing gate capacitance by using both high and low dielectric gate material

Life of this patent

Abstract

Claims9