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Photodiode Spectral Response Control Using Ion Damage

IP.com Disclosure Number: IPCOM000082493D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Fleming, DJ: AUTHOR

Abstract

A photodiode structure is described which permits its selective detection of optical radiation having wavelengths longer than a selected threshold wavelength.

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Photodiode Spectral Response Control Using Ion Damage

A photodiode structure is described which permits its selective detection of optical radiation having wavelengths longer than a selected threshold wavelength.

Fig. 1 shows a conventional photodiode structure comprised of an N + region 1, a P region 2, meeting at the PN junction 3. In conventional photodiodes, a diode is reversed biased by applying a negative potential to the N region 1 and a positive potential to the P region 2 and allowing light to be incident upon the N region 1, which will penetrate through the junction region 3 into the P region 2 where it will be absorbed producing photoelectrons. The photoelectrons produced in the P region 2 are swept by the superimposed electric field, into the PN junction region 3 and contribute to the junction current which can be measured in an external circuit.

Fig. 2 illustrates the structural modification of the conventional photodiode of Fig. 1, to permit the selective spectral response to incident light. The modified photodiode is fabricated by implanting ions through the front surface 7 of the N + region 1 at a sufficient energy, so as to produce a region of lattice damage 4 within the P region 2. The energy of the incident ions is selected such that the depth of the lattice damage region 4 corresponds to the penetration depth of the longest wavelength of light, which is desired to be detected by the photodiode.

The principle upon which the resulting spectrally responsive photodiode is based, is the reduced minority carrier lifetime of photoelectrons which m...