Patent ID: 8053309

Claim:
A method of fabricating a semiconductor device, the method comprising: preparing a semiconductor substrate that includes first and second regions; etching the semiconductor substrate to form a first trench in the first region and a second trench in the second region; forming sidewall oxide layers on inner surfaces of the first and second trenches; forming nitride layers on the sidewall oxide layers in the first and second trenches; forming a field oxide layer on the nitride layer in only the second trench, the field oxide layer filling the second trench; forming a gate oxide layer on the first and second regions; forming conductive layers on a first portion of the gate oxide layer in the first trench and on a second portion of the gate oxide layer in the second region; and forming impurity regions in the semiconductor substrate on sides of the conductive layer on the second portion of the gate oxide layer, wherein the conductive layer on the first portion of the gate oxide layer functions as an upper electrode of a capacitor, and wherein the sidewall oxide layer on the inner surface of the first trench, the nitride layer on the sidewall oxide layer in the first trench, and the first portion of the gate oxide layer on the nitride layer in the first trench function as a dielectric of the capacitor.