Semiconductor device having field stabilization film and method
View Patent ↗In one embodiment, a high voltage semiconductor device is formed with a first dielectric layer and a charge stabilization layer comprising a flowable glass formed over the first dielectric layer.
1. A method for enhancing breakdown voltage stability in a high voltage semiconductor device comprising the steps of:
providing a body of semiconductor material of a first conductivity type and having a resistivity greater than or equal to about one ohm-cm, wherein the body of semiconductor material has a first major surface;
forming a first dielectric layer in proximity to the first major surface;
forming a first doped region of a second conductivity type in the body of semiconductor material, wherein the first doped region and the first dielectric layer are in proximity to each other, and wherein the first doped region forms a high voltage junction with the body of semiconductor material; and
forming a spin-on glass layer overlying the first dielectric layer, wherein the spin-on glass layer has a refractive index less than 1.4, and wherein the spin-on glass layer is configured as a charge stabilization layer that provides the enhanced breakdown voltage stability, and wherein the spin-on glass layer terminates in proximity to an edge of the first doped region without overlying the entire first doped region.
2. The method of claim 1 , wherein the step of forming the spin-on glass layer comprises forming the spin-on glass layer having a refractive index in a range from about 1.36 to about 1.38.
3. The method of claim 1 , wherein the step of forming the first dielectric layer comprises forming a thermally grown silicon dioxide.
4. The method of claim 1 , wherein the step of forming the first dielectric layer comprises forming a thermally deposited silicon oxide.
5. The method of claim 1 , further comprising the step of forming a second dielectric layer overlying the spin-on glass layer.
6. The method of claim 1 , wherein the step of forming the first doped region includes forming the first doped region wherein the high voltage junction has a breakdown voltage greater than or equal to about 200 volts.
7. The method of claim 2 , wherein the step of forming the spin-on glass layer comprises forming the spin-on glass layer comprising one of a siloxane spin-on glass, a silicate spin-on glass, or a hydrogen silsesguioxanes spin-on glass.
8. The method of claim 5 , wherein the step of forming the second dielectric layer comprises forming a silicon nitride layer.
9. A method for forming a high voltage semiconductor device having enhanced breakdown voltage stability comprising the steps of:
providing a region of semiconductor material of a first conductivity type and having a resistivity greater than about one ohm-cm, wherein the region of semiconductor material has a first major surface;
forming a first extended drain region of a second conductivity type in the region of semiconductor material, wherein the first extended drain region forms a primary blocking junction and has a breakdown voltage greater than about 200 volts;
forming a body region of the first conductivity type in the region of semiconductor material;
forming a source region of the second conductivity type in the body region;
forming a first dielectric layer in proximity to at least a portion of the first major surface, wherein the first extended drain region and the first dielectric layer are in proximity to each other;
forming a gate structure adjacent the body region and the first extended drain region, wherein the high voltage semiconductor device is configured as an LDMOS device; and
forming a spin-on glass layer overlying the first dielectric layer, wherein the spin-on glass layer has a refractive index less than 1.4, and wherein the spin-on glass layer is configured as a charge stabilization layer that provides the enhanced breakdown voltage stability.
10. The device of claim 9 wherein the spin-on glass layer comprises a spin-on glass having a refracrive index in a range from about 1.36 to about 1.38.
11. The method of claim 9 , wherein the step of forming the first dielectric layer comprises forming a thermally grown silicon dioxide.
12. The method of claim 9 , wherein the step of forming the first dielectric layer comprises forming a thermally deposited silicon oxide.
13. The method of claim 9 , further comprising the step of forming a second dielectric layer overlying the spin-on glass layer.
14. The method of claim 10 , wherein the step forming the spin-on glass layer includes forming a spin-on glass layer comprising one of a siloxane spin-on glass, a silicate spin-on glass, or a hydrogen silsesguioxanes spin-on glass.
15. The method of claim 13 , wherein the step of forming the second dielectric layer comprises forming a silicon nitride layer.