Semiconductor transistor and method for making the same
AssigneeUnited Microelectronics Corp.
InventorChin-Cheng Chien
Life of this patent
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Abstract
A semiconductor transistor includes a substrate, a gate insulating layer positioned on the surface of the substrate, a gate positioned on the gate insulating layer, a channel region positioned in the substrate corresponding to the gate, and a source region and a drain region respectively positioned alongside the channel region. The source region and the drain region are mainly made of a first material and a second material, wherein the first material and the second material have a same lattice structure and different spacing. The source region and the drain region each include a main region in which a percentage of the second material is constant, and a peripheral region in which a percentage of the second material is graded.
Claims22
A semiconductor transistor comprising:
- a substrate;
- a gate insulating layer positioned on the surface of the substrate;
- a gate positioned on the gate insulating layer;
- a channel region positioned in the substrate corresponding to the gate;
- and
- a source region and a drain region respectively positioned alongside the channel region, the source region and the drain region including a first material and a second material, the first material and the second material having a same lattice structure and different spacing, the source region and the drain region each comprising a main region in which a percentage of the second material is constant, and a peripheral region in which a percentage of the second material is graded.
A method for forming a semiconductor transistor comprising:
- providing a substrate, the substrate comprising a gate insulating layer positioned on the surface of the substrate, a gate positioned on the gate insulating layer, and a channel region positioned in the substrate corresponding to the gate;
- forming two recesses in the substrate alongside the channel region;
- forming a first material and a second material in the recesses to respectively form two peripheral regions, the first material and the second material having a same lattice structure and different spacing, and a percentage of the second material in the peripheral regions being graded;
- and
- forming the first material and the second material in the recesses to respectively form two main regions above the peripheral regions, and a percentage of the second material in the main regions being constant.
Dependencies are inferred from the claim text.