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Gate Protective Diode Using Dual Electron Injector Structure

IP.com Disclosure Number: IPCOM000048262D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Chao, HH: AUTHOR

Abstract

This article describes a gate-protective diode that allows the gate voltage to go to negative, which is required for the level shift technique used in EAROM (electrically alterable read-only memory) devices to achieve lower program voltage.

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Gate Protective Diode Using Dual Electron Injector Structure

This article describes a gate-protective diode that allows the gate voltage to go to negative, which is required for the level shift technique used in EAROM (electrically alterable read-only memory) devices to achieve lower program voltage.

The program voltage level shift technique has been proposed to be used for making various EAROM cells to reduce the required program voltage level. In these approaches, a negative pulse on the erase line is required. Since the erase line is not decoded, it can be driven by an off-chip driver. However, the use of the conventional protective diode still limits the negative voltage to the substrate bias. This problem may be solved by using a dual-electron injector structure (DEIS) protective diode.

The equivalent circuits of the gate-protective diodes using DEIS are shown in Figs. 1 and 2. The current-voltage characteristic of the DEIS is shown in Fig. 3. By choosing the proper number of DEIS in series, the positive and negative thresholds of the protective diode can be obtained.

The function of the protective diode is described as follows: When the voltage applied to the pad of the gate is between the positive and negative thresholds of the protective diode, there is no current flow through the DEIS. In this case, the circuits are operated in the normal manner. But once the voltage applied to the pad of the gate becomes higher than the positive threshold or lower than...