SEMICONDUCTOR MEMORY DEVICE AND METHOD OF MANUFACTURING THE SAME

摘要

Provided is a semiconductor device, which prevents unnecessary voltage drop in a MOS transistor that is connected in series in a location between a booster circuit and a memory main body portion, to thereby operate on a low voltage and improve the ON/OFF ratio so that chip size shrinking and memory performance improvement are accomplished simultaneously. In a semiconductor memory device including a memory transistor portion and a select transistor portion, at least the select transistor portion is formed of a fin-shaped single-crystal semiconductor thin film.

主权项

1. A semiconductor memory device, comprising:
a select transistor portion comprising:
a first fin-shaped single-crystal semiconductor thin film formed of a semiconductor substrate of a first conductivity type;a drain region of a second conductivity type formed on a surface of the first fin-shaped single-crystal semiconductor thin film;a tunnel drain region of the second conductivity type formed on the surface of the first fin-shaped single-crystal semiconductor thin film apart from the drain region; anda select gate formed between the drain region and the tunnel drain region, the select gate being formed above an upper surface and side surfaces of the first fin-shaped single-crystal semiconductor thin film with a select gate oxide film interposed between the select gate and the first fin-shaped single-crystal semiconductor thin film; a memory transistor portion comprising:
a second fin-shaped single-crystal semiconductor thin film formed of the semiconductor substrate;a source region of the second conductivity type formed on a surface of the second fin-shaped single-crystal semiconductor thin film;a floating gate formed above the second fin-shaped single-crystal semiconductor thin film with a gate oxide film interposed between the second fin-shaped single-crystal semiconductor thin film and the floating gate, the gate oxide film extending from a surface of the tunnel drain region to an edge of the source region, the gate oxide film being formed on an upper surface and side surfaces of the second fin-shaped single-crystal semiconductor thin film and partially comprising a tunnel insulating film; anda control gate formed above the floating gate with an insulating film interposed between the floating gate and the control gate.