Methods for fabricating transistor gate structures
AssigneeTexas Instruments Incorporated
InventorsAntonio Luis Pacheco Rotondaro, Trace Quentin Hurd, Stephanie Watts Butler, Majid M. Mansoori
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Abstract
Methods are presented for fabricating MOS transistors, in which a sacrificial material such as silicon germanium is formed over a gate contact material prior to gate patterning. The sacrificial material is then removed following sidewall spacer formation to provide a recess at the top of the gate structure. The recess provides space for optional epitaxial silicon formation and suicide formation over the gate contact material without overflowing the tops of the sidewall spacers to minimize shorting between the gate and the source/drains in the finished transistor.
Claims15
A method of fabricating a MOS transistor in a wafer, comprising:
- forming a gate dielectric layer over a channel region of a semiconductor body;
- forming a polysilicon layer over the gate dielectric layer;
- forming a sacrificial material over the polysilicon layer;
- patterning the sacrificial material and the polysilicon layer to define a gate structure;
- forming at least one sidewall spacer along a lateral sidewall of the patterned gate structure;
- removing the sacrificial material from the patterned gate structure after forming the at least one sidewall spacer to expose at least a portion of the polysilicon and to provide a recess in the gate structure;
- forming first and second source/drains on opposite lateral sides of the channel region;
- and
- forming a silicide structure having a thickness in the recess of the gate structure, the thickness roughly equal to the remaining recess depth thereby substantially fill the recess.
A method of fabricating a MOS transistor in a wafer, comprising:
- forming a gate dielectric layer over a channel region of a semiconductor body;
- forming a gate contact layer over the gate dielectric layer;
- forming a sacrificial material over the gate contact layer;
- patterning the sacrificial material and the gate contact layer to define a gate structure;
- forming at least one sidewall spacer along a lateral sidewall of the patterned gate structure;
- removing the sacrificial material from the patterned gate structure after forming the at least one sidewall spacer to expose the gate contact layer and to provide a recess in the gate structure;
- growing epitaxial silicon material over the exposed gate contact layer in the recess of the gate structure after removing the sacrificial material;
- forming first and second source/drains on opposite lateral sides of the channel region;
- and
- forming a silicide structure having a thickness in the recess of the gate structure, the thickness roughly equal to the remaining recess depth thereby substantially fill the recess.
Dependencies are inferred from the claim text.