Lateral double diffused MOS device and method for manufacturing the same
View Patent ↗A lateral double diffused metal oxide semiconductor (LDMOS) device and a method of manufacturing the same. A LDMOS device may include a high voltage well formed over a substrate, a reduced surface field region formed thereover which may be adjacent a body region, and/or an isolation layer. An isolation layer may include a predetermined area formed over a reduced surface field region, may be partially overlapped with a top surface of a substrate and/or may include an area formed adjacent a high voltage well. A low voltage well may be formed over a substrate. A gate electrode may extend from a predetermined top surface of a body region to a predetermined top surface of an isolation layer. A drain region may be formed over a low voltage well. A source region may be formed over a body region and may have at least a portion formed under a gate electrode.
1. A method comprising:
forming a high voltage well over a substrate;
forming a reduced surface field region over said high voltage well;
forming a body region adjacent said reduced surface field region;
forming an isolation layer over the substrate including a predetermined area partially overlapped with said reduced surface field region;
forming a low voltage well over the substrate;
forming a gate electrode extending to a predetermined top surface of said isolation layer from a predetermined top surface of said body region; and
forming a drain region over said low voltage well;
forming a source region over said body region having at least a portion under said gate electrode;
forming a first conductivity type first impurity region under said reduced surface field region; and
forming a second conductivity type second impurity region under said first conductivity type first impurity region.
2. The method of claim 1 , wherein:
said isolation layer includes an area adjacent said high voltage well; and
at least a portion of at least one of said low voltage well and said drain region are formed over the substrate and below said area of said isolation layer adjacent said high voltage well.
3. The method of claim 1 , wherein forming said first and second impurity regions comprises:
forming a dielectric layer over said high voltage well;
forming a photoresist pattern over said dielectric layer; and
forming said first and second impurity regions by implanting a corresponding impurity ion using said photoresist pattern as ion implantation mask.
4. The method of claim 1 , wherein a depth of said reduced surface field region is between approximately 1 μm and 1.2 μm.
5. The method of claim 1 , wherein the substrate comprises a first conductivity and said body region is formed over said first conductivity type.
6. The method of claim 5 , wherein said first conductivity type comprises a p-type conductivity type.
7. The method of claim 1 , wherein at least one of said high voltage well, reduced surface field region, low voltage well, drain region and source region comprise second conductivity-types.
8. The method of claim 7 , wherein said second conductivity type comprises a n-conductivity type.