SEMICONDUCTOR DEVICES HAVING AN EDMOS TRANSISTOR AND METHOD OF FORMING THE SAME

摘要

A semiconductor device having an EDMOS(Extend Drain Metal Oxide Semiconductor) transistor and a method for fabricating the same are provided to reduce plane area of the EDMOS transistor by forming a counter doping region in a drift doping region. A source region(108s) and a drain region(108d) are formed on a semiconductor substrate to be separated from each other. A first gate dielectric(104) gap-filles a trench(102) formed on the semiconductor substrate between the source region and the drain region. The gate electric is adjacent to the drain region and separated from the source region. A second gate dielectric(110) is formed on the semiconductor substrate between the first gate dielectric and the source region. The second gate dielectric has a thickness thinner than that of the first gate dielectric. A gate electrode(112) is arranged on the first and second dielectrics. A drift doping region(106) is formed on the semiconductor substrate under the first gate dielectric and connected to the drain region. A counter doping region is formed in the drift doping region.