Power MOSFETs and methods for manufacturing the same
A semiconductor device and the method of manufacturing the same are provided. The semiconductor device includes a substrate, a source region, a drain region, a filed plate and a gate electrode. The source region is of a first conductivity type located at a first side within the substrate. The drain region is of the first conductive type located at a second side within the substrate opposite to the first side. The field plate is located over the substrate and between the source region and the drain region. A portion of the gate electrode is located over the field plate.
1. A semiconductor device, comprising:
a substrate;
a source region of a first conductivity type located at a first side within the substrate;
a drain region of the first conductive type located at a second side within the substrate opposite to the first side;
a field plate over the substrate and between the source region and the drain region;
a gate electrode having a first portion and a second portion, wherein the first portion of the gate electrode is located over the field plate;
a first dielectric having a top surface and a bottom surface, the top surface being in contact with the gate electrode and the bottom surface being in contact with the substrate;
a second dielectric located between the field plate and the substrate;
a third dielectric located between the first portion of the gate electrode and the field plate; and
a first spacer located on the substrate and in contact with the second dielectric.
2. The semiconductor device of claim 1 , wherein the first dielectric is located between the second portion of the gate electrode and the substrate.
3. The semiconductor device of claim 1 , wherein a thickness of the second dielectric is different from that of the third dielectric.
4. The semiconductor device of claim 1 , further comprising a second spacer being in contact with the second portion of the gate electrode and the field plate.
5. The semiconductor device of claim 1 , wherein a top surface of the gate electrode is substantially fully covered by a silicide layer.
6. The semiconductor device of claim 1 , wherein the substrate comprises:
a first region extending from a top surface of the substrate into the substrate, wherein the first region is of a second conductivity type;
a second region of the second conductivity type, formed at a first side within the first region wherein the source region is formed within the second region;
a drift region of the first conductivity type, formed at a second side opposite to the first side within the first region, wherein the drain region is formed within the drift region.
7. The semiconductor device of claim 6 , wherein an impurity concentration of the first region is different from an impurity concentration of the second region.
8. The semiconductor device of claim 6 , wherein an impurity concentration of the drift region is different from an impurity concentration of the drain region.
9. The semiconductor device of claim 6 , wherein the drift region is located beneath the field plate and the gate electrode.
10. The semiconductor device of claim 6 , wherein the second region is located beneath the second portion of the gate electrode and in contact with the drift region.
11. A semiconductor device, comprising:
a substrate;
a drift region with a first conductivity type, extending from a top surface of the substrate into the substrate and located in proximity to a first side of the substrate;
a second region with a second conductivity type, extending from the top surface of the substrate into the substrate and located in proximity to a second side of the substrate opposite to the first side;
a source region of a first conductivity type within the second region;
a drain region of the first conductive type within the drift region;
a field plate over the drift region;
a gate electrode over the drift region, wherein a top surface of the gate electrode is substantially fully covered by a silicide layer;
a first spacer on the substrate and adjacent to the field plate, a side of the first spacer aligning with a boundary of the drain region.
12. The semiconductor device of claim 11 , wherein a first portion of the gate electrode is over the field plate.
13. The semiconductor device of claim 12 , further comprising:
a gate oxide between a second portion of the gate electrode and the substrate;
a inter poly oxide located between the first portion of the gate electrode and the field plate.
14. The semiconductor device of claim 13 , further comprising a second spacer being in contact with the second portion of the gate electrode and the field plate.
15. A method of manufacturing a semiconductor device, the method comprising:
providing a substrate;
forming a source region of a first conductivity type at a first side within the substrate;
forming a drain region of the first conductive type located at a second side within the substrate opposite to the first side;
forming a field plate oxide over the substrate;
forming a field plate over the field plate oxide and between the source region and the drain region;
forming a gate electrode over the substrate after forming the field plate, a first portion of the gate electrode being over the field plate;
forming an inter poly oxide between the first portion of the gate electrode and the field plate; and
forming a first spacer on the substrate and in contact with the field plate oxide.
16. The method of claim 15 , wherein a thickness of the field plate oxide is different from that of the inter poly oxide.
17. The method of claim 15 , further comprising:
forming a gate dielectric over the substrate prior to the forming the gate electrode.
18. The method of claim 15 , further comprising forming a silicide layer to fully cover the gate electrode.
19. The method of claim 15 , wherein a second portion of the gate electrode is adjacent to-the field plate.
20. The method of claim 19 , further comprising:
forming a second spacer laterally covering the first portion and the second portion of the gate electrode.