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New Barrier for H+ Diffusion Into Solid Substrates

IP.com Disclosure Number: IPCOM000119267D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

deSouza, JP: AUTHOR [+3]

Abstract

This article describes a method which reduces H+ diffusion into solid substrates. In particular the diffusion of H+ present in the plasma during plasma-enhanced chemical vapor deposition (PECVD) of dielectric layers, such as Si3N4 or SiO2 into underlying GaAs, can be reduced. This enhances electrical activation of dopants in GaAs devices (MESFETs).

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New Barrier for H+ Diffusion Into Solid Substrates

      This article describes a method which reduces H+
diffusion into solid substrates.  In particular the diffusion of H+
present in the plasma during plasma-enhanced chemical vapor
deposition (PECVD) of dielectric layers, such as Si3N4 or SiO2 into
underlying GaAs, can be reduced.  This enhances electrical activation
of dopants in GaAs devices (MESFETs).

      The electrical activation of ion implanted dopants in
semiconductors is known to deteriorate when subjected to
H+-containing plasma.  The H+ effect on electrical properties is more
pronounced in compound semiconductors than in elemental
semiconductors.  The semiconductors are routinely subjected to
H+-containing plasma during IC fabrication.  For example, PECVD
Si3N4, SiO2 layers are typically used during fabrication of Si and
III-Vs ICs.  The gases used during the PECVD typically contain
hydrides of the constituent elements of the layers.  Therefore H+  is
present in abundance during the deposition of the layers and
interacts with the damage/dopant present in the underlying
substrates.  Although the outdiffusion of the H+ introduced during
the PECVD can be typically achieved at relatively low temperatures in
Si(< 300oC), such is not the case in III-V substrates.  The secondary
ion mass spectrometry analysis (SIMS) of H+ introduced into implanted
GaAs during PECVD of Si3N4 shows the H to be stable up to 850oC in
GaAs for time durations of up to a few minutes.  Such a stability of
the H may pose a problem in the modern submicron IC processes which
utilize rapid thermal annealing (RTA) in conjunction with the PECVD
layers.  This is b...