Semiconductor device and method of manufacturing the same
A semiconductor device is provided. The semiconductor device includes a semiconductor substrate, a P-well and an N-well disposed in the semiconductor substrate, a source disposed in the N-well and a drain disposed in the P-well, a shallow trench isolation (STI) structure disposed in the P-well, a gate structure disposed on the semiconductor substrate, wherein a portion of the gate structure extends into the semiconductor substrate and is disposed in a location corresponding to the STI structure.
1. A method of manufacturing a semiconductor device, comprising:
providing a semiconductor substrate;
forming a shallow trench isolation (STI) structure in the semiconductor substrate, wherein the STI structure is disposed in a location corresponding to where a P-well is to be formed;
performing ion implantation to form the P-well and an N-well in the semiconductor substrate, wherein the P-well is formed surrounding side and bottom portions of the STI structure;
forming a recess in the STI structure;
forming a gate structure on the semiconductor substrate, wherein a portion of the gate structure extends into the recess; and
performing ion implantation to form a source in the N-well and a drain in the P-well.
2. The method according to claim 1 , wherein forming the recess further comprises:
forming the recess by etching a portion of the STI structure, the portion of the STI structure having a predetermined thickness.
3. The method according to claim 2 , wherein the predetermined thickness ranges from about one-third to about half of a thickness of the un-etched STI structure.
4. The method according to claim 1 , wherein after forming the gate structure and prior to performing the ion implantation, the method further comprising:
forming spacers on opposite sides of the gate structure.
5. The method according to claim 1 , further comprising:
performing ion implantation to form an electrode in the N-well.
6. The method according to claim 1 , wherein the recess exposes at least one inner sidewall of the P-well.
7. The method according to claim 6 , wherein the recess exposes two inner opposite sidewalls of the P-well.
8. The method according to claim 1 , wherein the recess is disposed within the STI structure without exposing any inner sidewall of the P-well.