# US 5,352,913 A · Dynamic memory storage capacitor having reduced gated diode leakage

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- Number: US 5,352,913 A
- Document ID: US5352913A
- Status: Granted
- Kind: A
- Application number: 08/204,909
- Filed: 1994-03-02
- Granted: 1994-10-04
- Earliest claimed: 1990-12-05
- Assignees: Texas Instruments Incorporated
- Inventors: Gishi Chung; William R. McKee; Clarence W. Teng
- Web page: https://patentgrep.com/patent/US5352913A

## CPC

- H10B 12/038: {the capacitor being in a trench in the substrate}
- H10D 1/68: Capacitors having no potential barriers
- H10B: ELECTRONIC MEMORY DEVICES
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method of reducing gated diode leakage in trench capacitor type field plate isolated dynamic random access memory devices is disclosed. Trenches are etched into a face of a body of semiconductor material. Storage nodes surrounding the trenches are created. A polysilicon layer is formed on the trench walls. A storage dielectric layer is formed on the trench walls, adjacent to the layer of polysilicon on the trench walls, so that the layer of polysilicon on the trench walls lies between the storage dielectric layer and the storage node. The layer of polysilicon on the trench walls reduces leakage current from the storage node. A trench type field plate isolated random access memory cell structure is also disclosed.

## Claims

### Claim 1

A dynamic memory storage capacitor formed in a face of a semiconductor body, comprising:
a trench etched into the face of the semiconductor body, said trench having a semiconductor trench wall;
a layer of polysilicon on and directly touching said semiconductor trench wall;
a storage node in the face of the semiconductor body surrounding said trench wall in contact with said polysilicon;
a storage dielectric layer on top of said layer of polysilicon on said trench wall; and
a field plate extending down into said trench.

### Claim 2 (depends on 1)

The dynamic memory storage capacitor of claim 1 wherein the storage node contains implanted arsenic.

### Claim 3 (depends on 2)

The dynamic memory storage capacitor of claim 2 wherein the field plate is polysilicon.