Mosaic for ir imaging using pyroelectric sensors in a bipolar transistor array

Abstract

Abstract A monolithic integrated circuit for a bipolar transistor array of pyroelectric sensors to provide a spectral response to incident IR radiation. A matrix is provided by rows and columns of the sensors formed in a semiconductive substrate. Spaced parallel collector diffusions in the substrate are of one type conductivity which, in turn, receive base region diffusions of the other type conductivity thus forming a P-N junction. Pyroelectric thin films are deposited as isolated regions above the collector regions. In one form, the pyroelectric film has edge electrodes each extending to one of the underlying base and collector regions which are electrically insulated from the film by an oxide layer. An alternative to this form provides that the film is thermally insulated by an air gap from the collector regions. In a second alternative form, a surface electrode is used wherein the pyroelectric film is deposited directly on the collector and the surface electrode overlies the film and joins with the diffused base region. Emitter electrodes extend transverse to the orthogonal arrangement of the diffused collector and base regions. The emitter electrodes have a diffused contact region into one of the regions formed by the P-N junction for applying a reverse-biased charge to the junction. The pyroelectric charge neutralizes this reverse bias and the video signal is a measure of the current surge needed to restore the charge on the reverse-biased junction.

Inventors

• 👤 D Lampe
• 👤 E Irwin

Bibliographic Details