High voltage semiconductor device including field shaping layer and method of fabricating the same

1. A method of fabricating a high voltage semiconductor device, the method comprising:

forming a field shaping layer on substantially the entire surface of a first conductivity-type semiconductor substrate, wherein the impurity concentration of the field shaping layer is higher than that of the semiconductor substrate;

forming a second conductivity-type semiconductor layer on the field shaping layer;

forming a first insulating layer on the semiconductor layer;

forming a first conductivity-type body region in the semiconductor layer;

forming a second insulating layer on the semiconductor layer except for portions of the semiconductor layer and a portion of the body region;

forming a gate on a portion of the first insulating layer and a portion of the second insulating layer, wherein the gate overlaps a portion of the body region and a portion of the semiconductor layer;

forming a second conductivity-type source region in the body region and a drain region in the body region, wherein the source region is separated from the drain region.

2. The method of claim 1 , wherein the field shaping layer is formed by blanket ion-implanting first conductivity-type impurities into the semiconductor substrate.

3. The method of claim 2 , wherein the impurity concentration of the field shaping layer is lower than that of the body region.

4. The method of claim 1 , wherein forming the body region comprises forming a top region in a portion of the semiconductor layer between the source region and the drain region.

5. The method of claim 4 , wherein the top region has the same conductivity type as that of the field shaping layer, and the impurity concentration of the top region is higher than that of the field shaping layer.

6. The method of claim 1 , further comprising,

before the field shaping layer is formed, forming a first conductivity-type bottom region for device isolation in the semiconductor substrate, and

after the semiconductor layer is formed and before the body region is formed, forming a well region for device isolation in a portion of the semiconductor layer between the bottom region and the body region.

7. The method of claim 1 , wherein the forming the gate further comprises

forming a conductive layer pattern on the second insulating layer and after the forming the gate, the method further comprises:

forming a first interlayer insulating layer having first contact holes that expose a portion of the source region, a portion of the drain region, and a portion of the conductive layer pattern;

forming a bottom source electrode and a bottom drain electrode on the first interlayer insulating layer, wherein the bottom source electrode and top source electrode are electrically connected to the source region and the drain region through some of the first contact holes;

forming a second interlayer insulating layer having second contact holes on the bottom source electrode, the bottom drain electrode, and the first interlayer insulating layer, wherein the second contact holes expose a portion of the bottom source electrode, a portion of the bottom drain electrode, and a portion of the conductive layer pattern;

forming a top source electrode and a top drain electrode on the second interlayer insulating layer, wherein the top source electrode is electrically connected to the bottom source electrode through one of the second contact holes, and the top drain electrode is electrically connected to the conductive layer pattern through others of the first and second contact holes and to the bottom drain electrode through another of the second contact holes.