Patent ID: 6723649
Filing Date: 2004-04-20
Classification: H01L

Abstract:
A method of fabricating a semiconductor memory device, comprising:forming a sacrificial oxide layer on a semiconductor substrate; forming a photoresist layer on the sacrificial oxide layer; patterning the photoresist layer to form a plurality of openings where bit lines are to extend respectively; implanting first type ions into the semiconductor substrate through the openings; implanting second type ions into the semiconductor substrate through the openings, wherein the first type ions and the second type ions are electrically opposite and the implantation depth of the second type ions are deeper than the first type ions; removing the photoresist layer and the sacrificial oxide layer; growing a gate oxide and a field oxide simultaneously on the non-implanted and the implanted regions of the semiconductor layers respectively; and depositing a gate conductive layer on the semiconductor substrate.