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Solid-State Memory

IP.com Disclosure Number: IPCOM000039022D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 200K

Publishing Venue

IBM

Related People

Guidotti, D: AUTHOR [+2]

Abstract

Non-radiative recombination centers in GaAs can store energy that is written by energy beams and sensed by optical means. III-V compounds, such as GaAs, luminesce when illuminated with energy beams, such as an electron beam or laser beam. The incident energy beam creates electron-hole pairs which recombine in part radiatively giving rise to light output at photon energies slightly below the band gap of the semiconductor. The emitted light can be easily (Image Omitted) detected using photodetectors of several types, i.e., Si photodiodes, S-I cathodes, etc. In III-V compounds, such as GaAs, a time degradation of the emitted photoluminescence takes place due to the incident energy beam, leading to dark spots wherever the incident beam has been allowed to dwell for some period of time.

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Solid-State Memory

Non-radiative recombination centers in GaAs can store energy that is written by energy beams and sensed by optical means. III-V compounds, such as GaAs, luminesce when illuminated with energy beams, such as an electron beam or laser beam. The incident energy beam creates electron-hole pairs which recombine in part radiatively giving rise to light output at photon energies slightly below the band gap of the semiconductor. The emitted light can be easily

(Image Omitted)

detected using photodetectors of several types, i.e., Si photodiodes, S-I cathodes, etc. In III-V compounds, such as GaAs, a time degradation of the emitted photoluminescence takes place due to the incident energy beam, leading to dark spots wherever the incident beam has been allowed to dwell for some period of time. The higher the intensity of the incident beam, the faster the luminescence decay. This is shown in Fig. 1, where the decay of luminescence due to incident Kr laser illumination is shown for several laser intensities. By moving the incident writing beam with respect to the wafer, patterns can be written, including dots representing ones or zeros. The same beam scanned quickly over the wafer and/or reduced in intensity can be used to read the pattern. Fig. 2 shows patterns of lines 15 microns wide written onto a GaAs wafer and read by the same laser. Using this principle, a memory can be made using III-V semiconductors like GaAs as the storage medium, where computer co...