Radiation detecting device

• US 3,896,309 A
• Filed: 05/21/1973
• Issued: 07/22/1975
• Est. Priority Date: 05/21/1973
• Status: Expired due to Term

• Current Assignee: Edgar L. Irwin, Jack L. Halsor, Pieter Dewit
• Original Assignee: Edgar L. Irwin, Jack L. Halsor, Pieter Dewit
• Inventors: Irwin, Edgar L., Halsor, Jack L., Dewit, Pieter
• Primary Examiner(s): Stolwein, Walter
• Application Number:
  US05/362,138
• Time in Patent Office: 792 Days
• Field of Search: 250/370,371,211J,238 317/235B,235H,235N,235Y,248
• US Class Current: 257/254
• CPC Class Codes: G01J 5/40 using bimaterial elements
• CPC Class Codes: H01L 31/1136 the device being a metal-insulator-semiconductor field-effect transistor

Abstract

A multiwavelength radiation detector having the ability to integrate received radiation. The detector comprises a modified MOS field effect transistor wherein the gate takes the form of a cantilevered member formed from two layers of material of differing coefficients of expansion, one above the other. The free end of the cantilevered member extends over the space between the source and drain regions of the field effect transistor. As radiation impinges upon the cantilevered member, it will bend, causing the distance between the gate and the underlying semiconductive substrate to vary. In this manner, and assuming a constant gate voltage, the surface conductivity of the substrate between the source and drain regions can be made to vary as function of the integrated value of radiation which has impinged on the cantilevered member over a selected time interval. Such detectors can be connected in arrays, such that a radiation pattern over an area can be determined.

Claims

1. A radiation detecting device for integrating incident radiation comprising a substrate of semiconductive material of one type conductivity, spaced regions of the other type conductivity formed in a surface of said substrate, an oxide layer covering at least selected portions of said surface of the substrate, a cantilevered member secured to said oxide layer at an area removed from said spaced regions and having a free end extending over the area of said substrate between said spaced regions, said cantilevered member being formed from at least two layers of different materials one above the other, the different materials having different coefficients of expansion, source and drain electrodes connected to said spaced regions, and a gate electRode connected to said cantilevered member, the arrangement being such that upon exposure to radiation and resulting heating of the cantilevered member, it will bend due to the different coefficients of expansion of said materials and vary the spacing between said cantilevered member and the substrate, whereby the surface conductivity characteristics of the substrate between the spaced regions can be made to vary as a function of the amount of radiation absorbed by the cantilevered member.

2. The device of claim 1 wherein said spaced regions form the drain and source of an isolated gate field effect transistor and said cantilevered member comprises the gate of said field effect transistor.

3. The device of claim 2 wherein one of said materials from which the cantilevered member is formed is metallic while the other material is a dielectric, the metallic material forming said gate electrode.

4. The device of claim 3 wherein one of said materials from which the cantilevered member is formed comprises gold while the other material comprises glass.

5. The device of claim 1 wherein the materials from which the cantilevered member is formed are both metallic.

6. The device of claim 1 wherein said free end of the cantilevered member is raised above said oxide layer and is connected through a bent portion to the other end of the member which is secured to said oxide layer.