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Stabilization of Luminescence from Porous Silicon by Encapsulation

IP.com Disclosure Number: IPCOM000103708D
Original Publication Date: 1993-Jan-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 46K

Publishing Venue

IBM

Related People

Collins, R: AUTHOR [+4]

Abstract

This article describes a method for stabilizing the intensity of luminescence from porous silicon. Porous silicon, formed by electrochemical etching, can be made to luminesce efficiently in the visible. This luminescence is quite stable as long as the sample is kept in a non-oxidizing ambient. When oxygen and irradiation are present simultaneously, the luminescence efficiency decreases rapidly by more than a factor of 20.

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Stabilization of Luminescence from Porous Silicon by Encapsulation

       This article describes a method for stabilizing the
intensity of luminescence from porous silicon. Porous silicon, formed
by electrochemical etching, can be made to luminesce efficiently in
the visible.  This luminescence is quite stable as long as the sample
is kept in a non-oxidizing ambient.  When oxygen and irradiation are
present simultaneously, the luminescence efficiency decreases rapidly
by more than a factor of 20.

      Luminescent devices fabricated from porous silicon could find a
wide range of applications.  These could be as separate devices or
monolithically integrated with silicon-based electronics.  However,
for these to be useful, the luminescence efficiency must be stable,
and this invention is applicable to any use of porous silicon for
light-emitting applications.  Disclosed here is an encapsulant which
prevents the oxygen from coming in contact with the porous silicon,
thus reducing the degradation when illumination and oxygen are
present simultaneously.

      This invention consists of encapsulating the porous silicon
film with parylene to prevent it from coming in contact with oxygen.
A number of encapsulants, such as spin-on glasses and PMMA, have been
found to have two problems.  The first is that the process of
applying these encapsulants often degrades the luminescence, and,
second, they do not prevent the oxygen-induced degradation.
Parylene, deposited...