Browse Prior Art Database

Minority Charge Detector

IP.com Disclosure Number: IPCOM000074770D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Patrin, NA: AUTHOR

Abstract

This is a minority charge detector for semiconductor devices that uses substrate depletion region fringing to control conduction of an FET, thereby detecting the presence or absence of charge in the semiconductor body. The device comprises semiconductor body 10, having on its surface insulating layer 14 over which there is deposited metallic electrode 16 and a layer of high-resistivity semiconductor material 18. High resistivity layer 18 is connected at one end through conductive pad 20 to gate electrode 22 of FET 12 and through resistor 25 to voltage supply 26. The other end of layer 18 is connected to body 10 near the edge of electrode 16.

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Minority Charge Detector

This is a minority charge detector for semiconductor devices that uses substrate depletion region fringing to control conduction of an FET, thereby detecting the presence or absence of charge in the semiconductor body. The device comprises semiconductor body 10, having on its surface insulating layer 14 over which there is deposited metallic electrode 16 and a layer of high- resistivity semiconductor material 18. High resistivity layer 18 is connected at one end through conductive pad 20 to gate electrode 22 of FET 12 and through resistor 25 to voltage supply 26. The other end of layer 18 is connected to body 10 near the edge of electrode 16.

When a voltage, of the proper sign and magnitude, is applied to electrode 16 by power supply 28, depletion region 30 is created in the body. This region 30 will have fringing fields extending into body 10 and into high-resistivity material 18 beyond the edge of electrode 16. The edges of this fringing field, in material 18, is shown as line 32.

If a suitable voltage from supply 26 is now applied to material 18 and to gate 22, FET 12 will turn on and conduct provided the voltage from supply 26 is equal to or greater than the threshold voltage of FET 12.

When charges shown as crosses 24 are introduced into depletion region 30, the region 30 shrinks back in body 10 to line 34 and in material 18 to line 33. This shrinkage of the depletion region 30 opens a conductive path between the high-resistivity mat...