Semiconductor device and method for forming the same
AssigneeWinbond Electronics Corp.
InventorsHsueh-Yen CHEN, Shih-Ming WANG
Life of this patent
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Abstract
A semiconductor device is provided. The semiconductor device includes a substrate, a gate stack layer formed over the substrate, a silicon germanium (SiGe) channel layer formed in the substrate and covered by the gate stack layer, first and second source/drain (S/D) regions, and first and second lightly doped drain (LDD) layers. The first and second S/D regions are formed in the substrate on a first side and a second side opposite to the first side of the gate stack layer, respectively. The first LDD layer is disposed between the SiGe channel layer and the first S/D region, and the second LDD layer is disposed between the SiGe channel layer and the second S/D region. The first and second LDD layers include SiGe materials.
Claims20
A semiconductor device, comprising:
- a substrate;
- a gate stack layer formed over the substrate;
- a silicon germanium channel layer formed in the substrate and covered by the gate stack layer;
- a first source/drain (S/D) region and a second S/D region formed in the substrate on a first side and a second side opposite to the first side of the gate stack layer, respectively;
- a first lightly doped drain (LDD) layer and a second LDD layer formed in the substrate, wherein
- the first LDD layer is disposed between the silicon germanium channel layer and the first S/D region, and
- the second LDD layer is disposed between the silicon germanium channel layer and the second S/D region,
- wherein the first LDD layer and the second LDD layer include silicon germanium materials.
A method for forming a semiconductor device, comprising:
- forming a first recess and a second recess in a substrate and respectively on a first side and an opposite second side of a channel region of the substrate;
- forming a first doped silicon germanium epitaxial layer in the first recess, and forming a second doped silicon germanium epitaxial layer in the second recess;
- removing the substrate in the channel region to form a third recess in the substrate, wherein the third recess exposes a sidewall of the first doped silicon germanium epitaxial layer and a sidewall of the second doped silicon germanium epitaxial layer;
- forming an undoped silicon germanium epitaxial layer in the third recess;
- and
- forming a gate structure on the substrate to cover the undoped silicon germanium epitaxial layer, a portion of the first doped silicon germanium epitaxial layer, and a portion of the second doped silicon germanium epitaxial layer.
A method for forming a semiconductor device, comprising:
- forming a recess in a substrate;
- forming a doped silicon germanium (SiGe) epitaxial layer in the recess;
- forming a channel opening in the doped SiGe epitaxial layer to expose the substrate and separating the doped SiGe epitaxial layer into a first portion and a second portion on two opposite sides of the channel opening, respectively;
- forming a first undoped SiGe epitaxial layer in the channel opening;
- and
- forming a gate structure over the substrate to cover the first undoped SiGe epitaxial layer, a portion of the first portion and a portion of the second portion.
Dependencies are inferred from the claim text.