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Ion Implanted, Bidirectional High Voltage Metal Oxide Semiconductor Field Effect Transistor

IP.com Disclosure Number: IPCOM000079216D
Original Publication Date: 1973-May-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Fang, F: AUTHOR [+3]

Abstract

The structure shown in the figure is an ion implanted, bidirectional, high-voltage field-effect transistor (FET). The open metal-oxide semiconductor (MOS) FET structure uses an ion implanted region around all source-drain diffusion edges which are identified in the figure as source-drain 1 and source-drain 2, which are not covered by gates 1. 2. The function of this implant is to reduce the radius of curvature, and thereby increase the breakdown voltage to a value approaching bulk breakdown. The ion implant in the gap between gates 1, 2 provides continuity of the channel when the device is operating as a MOSFET. Gates 1, 2 may be fabricated from either metal or polycrystalline silicon.

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Ion Implanted, Bidirectional High Voltage Metal Oxide Semiconductor Field Effect Transistor

The structure shown in the figure is an ion implanted, bidirectional, high- voltage field-effect transistor (FET). The open metal-oxide semiconductor (MOS) FET structure uses an ion implanted region around all source-drain diffusion edges which are identified in the figure as source-drain 1 and source-drain 2, which are not covered by gates 1. 2. The function of this implant is to reduce the radius of curvature, and thereby increase the breakdown voltage to a value approaching bulk breakdown. The ion implant in the gap between gates 1, 2 provides continuity of the channel when the device is operating as a MOSFET. Gates 1, 2 may be fabricated from either metal or polycrystalline silicon.

This is an advantageous embodiment of a high-voltage MOSFET, because the ion implantation utilized in the device of the figure can also be used to improve the characteristics of low-voltage devices (threshold, density, depletion mode, load devices) on the same chip.

In connection with the arrangement, it should be noted that the ion implantation around the source-drain regions does not extend into the channel region and, as a result, a high impedance is avoided when the MOSFET operates bidirectionally.

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