Semiconductor device and fabrication method thereof
View Patent ↗A semiconductor device and a fabrication method thereof are provided. The semiconductor device includes a P type well region and an N type well region formed in a substrate, a gate insulating layer having a non-uniform thickness and formed on the P type well region and the N type well region, a gate electrode formed on the gate insulating layer, a P type well pick-up region formed in the P type well region, and a field relief oxide layer formed in the N type well region between the gate electrode and the drain region.
1. A semiconductor device, comprising:
a lateral double diffused metal oxide semiconductor field effect transistor (LDMOS) device formed in a first region of the semiconductor device; and
a complementary MOS (CMOS) device formed in a second region of the semiconductor device,
wherein the LDMOS device comprises:
a P type well region and an N type well region formed in a substrate;
a gate insulating layer having a non-uniform thickness and formed on the P type well region and the N type well region;
a gate electrode formed on the gate insulating layer;
a P type well pick-up region formed in the P type well region;
a drain region formed in the N type well region; and
a field relief oxide layer formed in the N type well region between the gate electrode and the drain region,
wherein the P type well region of the LDMOS device and a P type well region of the CMOS device have substantially the same depth, and the N type well region of the LDMOS device and an N type well region of the CMOS device have substantially the same depth.
2. The semiconductor device of claim 1 , wherein the gate insulating layer on the P type well region has areas of two or more different thicknesses.
3. The semiconductor device of claim 1 , wherein the gate insulating layer comprises a thin gate insulating layer and a thick gate insulating layer.
4. The semiconductor device of claim 3 , further comprising:
a source region formed in the P type well region,
wherein the thin gate insulating layer, the thick gate insulating layer, and the field relief oxide layer are formed between the source region and the drain region.
5. The semiconductor device of claim 4 , wherein the P type well pick-up region is spaced apart from the source region by a device isolation layer.
6. The semiconductor device of claim 3 , further comprising a PN junction region at an interface between the P type well region and the N type well region,
wherein a distance between an interface of the thin gate insulating layer and the thick gate insulating layer and the PN junction region is less than a distance from the PN junction region to the field relief oxide layer.
7. The semiconductor device of claim 6 , wherein:
the thick gate insulating layer is formed on one portion of the P type well region and the N type well region; and
the thin gate insulating layer is formed on the other portion of the P type well region.
8. The semiconductor device of claim 3 , further comprising a PN junction region at an interface between the P type well region and the N type well region,
wherein a distance between an interface of the thin gate insulating layer and the gate insulating layer and the PN junction is less than an overlapping distance between the P type well and the thin gate insulating layer.
9. The semiconductor device of claim 1 , further comprising a low concentration N type doping region in the P type well region.
10. The semiconductor device of claim 1 , wherein the field relief oxide layer overlaps the gate electrode.
11. The semiconductor device of claim 1 , wherein the P type well region and the N type well region include a retrograde well.
12. The semiconductor device of claim 1 , wherein the gate insulating layer comprises a silicon oxynitride layer.
13. The semiconductor device of claim 1 , wherein the CMOS device comprises:
a CMOS well region;
a gate insulating layer formed on the CMOS well region;
a CMOS gate electrode formed on the gate insulating layer;
a CMOS source region formed in the CMOS well region; and
a CMOS drain formed in the CMOS well region.
14. A lateral double diffused metal oxide semiconductor field effect transistor (LDMOS) device, comprising:
a P type well region and an N type well region thereby forming a PN junction region in a substrate;
a source region formed in the P type well region;
a drain region formed in the N type well region;
a thin gate insulating layer, a thick gate insulating layer, and a relief oxide layer formed between the source region and the drain region;
a gate electrode formed on the thin gate insulating layer, the thick gate insulating layer, and the relief oxide layer; and,
a P type well pick-up region formed in the P type well region,
wherein the gate electrode is in direct contact with the thin gate insulating layer, the thick gate insulating layer, and the relief oxide layer; and,
wherein a top surface of the thick gate insulating layer is coplanar with a top surface of the relief oxide layer.
15. The semiconductor device of claim 14 , wherein:
the thick gate insulating layer is formed on a first portion of the P type well region and the N type well region; and
the thin gate insulating layer is formed on a second portion of the P type well region.
16. The semiconductor device of claim 14 , wherein a distance between an interface of the thin gate insulating layer and the thick gate insulating layer and the PN injunction region is less than a distance from the PN junction region to the field relief oxide layer.
17. The semiconductor device of claim 14 , wherein a distance between an interface of the thin gate insulating layer and the thick gate insulating layer and the PN injunction region is less than an overlapping distance between the P type well and the thin gate insulating layer.
18. The semiconductor device of claim 14 , wherein the field relief oxide layer has a greater thickness than the thick gate insulating layer.