Gate structure in a trench region of a semiconductor device and method for manufacturing the same
View Patent ↗Disclosed are a gate structure in a trench region of a semiconductor device and a method for manufacturing the same. The semiconductor device includes a pair of drift regions formed in a semiconductor substrate; a trench region formed between the pair of drift regions; an oxide layer spacer on sidewalls of the trench region; a gate formed in the trench region; and a source and a drain formed in the pair of the drift regions, respectively.
1. A method for manufacturing a semiconductor device, the method comprising the steps of:
forming first and second drift regions in a semiconductor substrate;
forming an oxide layer on the substrate such that the oxide layer partially overlaps the first and second drift regions;
forming a trench between the first and second drift regions;
forming an oxide spacer on sidewalls of the trench;
forming an insulating layer at a bottom of the trench;
forming a gate in the trench and on the oxide layer;
forming a spacer on sidewalls of the gate; and
forming a source in one of the first and second drift regions and a drain in the other of the first and second drift regions.
2. The method according to claim 1 , wherein the step of forming the oxide layer includes:
forming a mask pattern on the substrate;
etching the substrate to a predetermined depth;
depositing the oxide layer over an entire surface of the semiconductor substrate; and
planarizing the oxide layer.
3. The method according to claim 1 , wherein the trench has a depth equal to or less than that of the first and second drift regions and a width equal to or less than a length of the oxide layer.
4. The method according to claim 3 , wherein the width of the trench is less than the length of the oxide layer.
5. The method according to claim 1 , wherein the spacer comprises silicon nitride.
6. The method according to claim 1 , wherein the first and second drift regions are symmetrical to and spaced apart from each other in a horizontal direction.
7. A method for manufacturing a semiconductor device, the method comprising the steps of:
forming first and second drift regions in a semiconductor substrate;
forming an oxide layer on the substrate such that the oxide layer overlaps with each of the first and second drift regions;
forming a nitride layer on the substrate;
forming a trench between the first and second drift regions;
forming an oxide spacer on sidewalls of the trench;
forming an insulating layer at a bottom of the trench;
removing the nitride layer;
forming a gate in the trench region and at least partially on the oxide layer; and
forming a source in one of the first and second drift regions and a drain in the other of the first and second drift regions.
8. The method according to claim 7 , wherein the trench has a depth less than that of the first and second drift regions and a width less than a length of the oxide layer.
9. The method according to claim 7 , further comprising forming a nitride spacer on sidewalls of the gate.
10. A method for manufacturing a semiconductor device, the method comprising the steps of:
forming first and second drift regions in a semiconductor substrate;
forming a mask pattern on the substrate;
etching the substrate to a predetermined depth;
depositing the oxide layer over an entire surface of the semiconductor substrate such that the oxide layer partially overlaps the first and second drift regions;
planarizing the oxide layer;
forming a trench between the first and second drift regions;
forming an oxide spacer on sidewalls of the trench;
forming an insulating layer at a bottom of the trench;
forming a gate in the trench and on the oxide layer; and
forming a source in one of the first and second drift regions and a drain in the other of the first and second drift regions.
11. The method according to claim 10 , wherein the oxide layer has a length greater than the distance between the first and second drift regions.
12. The method according to claim 10 , wherein the trench has (i) a depth equal to or less than that of the first and second drift regions and (ii) a width equal to or less than a length of the oxide layer.
13. The method according to claim 10 , wherein the width of the trench is less than the length of the oxide layer.
14. The method according to claim 10 , further comprising forming a nitride layer on the substrate prior to forming the trench between the first and second drift regions.
15. The method according to claim 14 , further comprising removing the nitride layer after forming the insulating layer at the bottom of the trench.
16. The method according to claim 10 , further comprising forming a nitride spacer on sidewalls of the gate.
17. The method according to claim 10 , wherein the first and second drift regions are symmetrical to and spaced apart from each other in a horizontal direction.