Patent ID: 8310004
Filing Date: 2012-11-13
Classification: H01L

Abstract:
1. A semiconductor device comprising: a substrate; a device isolation film formed in the substrate and having a first depth in the substrate; a source region and a drain region, both of which are of a first conductivity and arranged in the substrate; a channel region of a second conductivity arranged, in the substrate, in a first direction between the source region and the drain region; a first low-concentration region of the first conductivity formed in the substrate between the source region and the channel region and having a first conductivity dopant concentration lower than a first conductivity dopant concentration of the source region; a second low-concentration region of the first conductivity formed in the substrate between the drain region and the channel region and having a first conductivity dopant concentration lower than a first conductivity dopant concentration of the drain region, a trench formed in the substrate between the first low-concentration region and the second low-concentration region and having a side surface extending in the first direction between the first low-concentration region and the second low-concentration region; a gate insulating film formed in the trench; and a gate electrode formed in the trench through the gate insulating film and having a second depth in the substrate, wherein the second depth of the gate electrode serves as a gate width such that a portion of the channel region sideward, in a second direction crossing the first direction, from the side surface of the trench is arranged between the first low-concentration region and the second low-concentration region, wherein the first low-concentration region and the second low-concentration region each includes a first portion extending in said substrate, having a third depth shallower than the first depth of the device isolation film and contacting the device isolation film at a depth shallower than the first depth of the device isolation film.