# US 8,785,334 B2 · Select transistor, method for making select transistor, memory device, and method for manufacturing memory device

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- Number: US 8,785,334 B2
- Document ID: US8785334B2
- Status: Granted
- Kind: B2
- Application number: 13/478,573
- Filed: 2012-05-23
- Published: 2012-11-29
- Granted: 2014-07-22
- Earliest claimed: 2011-05-27
- Assignees: Tokyo Electron Limited
- Applicants: Yoshitsugu Tanaka
- Inventors: Yoshitsugu Tanaka
- Web page: https://patentgrep.com/patent/US8785334B2

## CPC

- H10B 41/35: with a cell select transistor, e.g. NAND
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A select transistor for use in a memory device including a plurality of memory transistors connected in series includes a tunnel insulating layer formed on a semiconductor substrate, a charge storage layer formed on the tunnel insulating layer, a blocking insulating layer formed on the charge storage layer and configured to be irradiated with a gas cluster ion beam containing argon as source gas, a gate electrode formed on the blocking insulating layer, and a source/drain region formed within the semiconductor substrate at both sides of the gate electrode.

## Claims

### Claim 1

A method for manufacturing a memory device including a plurality of memory transistors connected in series and select transistors disposed in both ends of the plurality of memory transistors, comprising:
forming a tunnel insulating layer on a semiconductor substrate;
forming a charge storage layer on the tunnel insulating layer;
forming a blocking insulating layer on the charge storage layer;
selectively irradiating the blocking insulating layer in a region where the select transistor is to be formed, with a gas cluster ion beam containing argon as source gas;
forming a gate electrode on the blocking insulating layer;
patterning the tunnel insulating layer, the charge storage layer, blocking insulating layer and the gate electrode; and
forming a source/drain region within the semiconductor substrate at both sides of the patterned gate electrode.

### Claim 2 (depends on 1)

The method of claim 1, wherein the blocking insulating layer is made of aluminum oxide.