US 2007/0190724 A1 · SEMICONDUCTOR DEVICE

Abstract

It is an object to provide a semiconductor device capable of holding multibit information in one memory cell also when scaling for a nonvolatile memory progresses, and a method of manufacturing the semiconductor device. A trench (TRI) is formed in a channel portion of an MONOS transistor. Then, a source side portion and a drain side portion in a silicon nitride film (122) of a gate insulating film (120) which interpose the trench (TR1) are caused to function as first and second electric charge holding portions capable of holding electric charges (CH1) and (CH2). In the case in which the electric charges (CH1) are trapped and the electric charges (CH2) are then trapped, thus, a portion (130a) of a gate electrode (130) in the trench (TR1) functions as a shield. If a fixed potential is given to the gate electrode (130), the second electric charge holding portion is not influenced by an electric field (EF1) induced by the electric charges (CH1) so that the trapping of the electric charges (CH2) is not inhibited.

Claims11

Dependent claims

A method of manufacturing a semiconductor device, comprising:

providing a semiconductor substrate having a trench formed in a surface of said semiconductor substrate;
and
forming an MIS (Metal Insulator Semiconductor) transistor including the steps of
forming a source region formed to face said surface in said semiconductor substrate;
forming a drain region formed to face said surface in said semiconductor substrate, said drain region formed apart from said source region on an opposite side of said trench;
forming a gate insulating film formed on at least a portion of said surface which is interposed between said source region and said drain region within said trench;
and
forming a gate electrode formed on said gate insulating film at least within said trench,
wherein the step of forming the gate insulating film includes forming first and second electric charge holding portions configured to hold an electric charge in said gate insulating film with said trench interposed therebetween.

6 more elements

Dependencies are inferred from the claim text.

Semiconductor device

Life of this patent

Semiconductor device

Life of this patent

Abstract

Claims11