Browse Prior Art Database

Electrically Alterable Silicon Structure

IP.com Disclosure Number: IPCOM000048948D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Anderson, LL: AUTHOR

Abstract

The basic silicon structure employed is a field-effect transistor with a buried gate structure. The double-polysilicon structure (DPS) is similar to the CFET structure in that multilevel metal is employed in making interconnections. This structure departs from the latter structure in several ways. DEPARTURES 1. A modification is made in the form and geometry of the buried gate, such that the polysilicon gate 1 has an extension over thin oxide material in the region of the enhanced channel. This particular extension resembles a "tail" added to the polysilicon gate 1, and shall be called the "tail gate". 2. The polysilicon gate 2 has an extension which covers (shadows) the polysilicon gate 1 addition. This shall be called the "shadow gate".

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 74% of the total text.

Page 1 of 2

Electrically Alterable Silicon Structure

The basic silicon structure employed is a field-effect transistor with a buried gate structure. The double-polysilicon structure (DPS) is similar to the CFET structure in that multilevel metal is employed in making interconnections. This structure departs from the latter structure in several ways. DEPARTURES
1. A modification is made in the form and geometry of the buried

gate, such that the polysilicon gate

1 has an extension over thin oxide material in the region

of the enhanced channel. This particular extension

resembles a "tail" added to the polysilicon gate 1, and

shall be called the "tail gate".
2. The polysilicon gate 2 has an extension which covers

(shadows) the polysilicon gate 1 addition. This shall be

called the "shadow gate".

The modifications to the structure provide an electrically alterable, non- volatile storage element which requires no periodic refresh. The structure is programmable by applying a "programming charge" on the shadow gate. Principles Employed

Quantum mechanical tunneling (Fowler - Nordheim tunneling) through the thin gate oxide layer allows bi-directional charging of the buried tail gate. The charge is achieved at low energy levels with small power dissipation. The low energy charge carriers may pass a short distance without causing breakdown in the silicon due to excessive heating. The oxide thickness below the buried tail gate is on the order of 200 angstroms, which will allow a programmi...