Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!utpsych!webber
From: webber@psych.toronto.edu (Bob Webber)
Newsgroups: comp.arch
Subject: Re: GaAs considered dead , indium phosphide, rod logic?
Message-ID: <1989Nov30.230012.11752@psych.toronto.edu>
Date: 30 Nov 89 23:00:12 GMT
References: <1376@argus.UUCP> <10508@encore.Encore.COM>
Reply-To: webber@psych.toronto.edu (Bob Webber)
Organization: Psychology, U. of Toronto
Lines: 27

In article <10508@encore.Encore.COM> jdarcy@pinocchio.encore.com (Jeff d'Arcy) writes:
>While we're at it, what is "ballistic transistor" technology.  I see
>images of microchips with little microrocket engines, but somehow I
>don't think that's what ER was talking about.
>
>Jeff d'Arcy     OS/Network Software Engineer     jdarcy@encore.com
>  Encore has provided the medium, but the message remains my own

A simplified explanation: electrons are accelerated towards the gate
so that the delay time between a change of state at the gate and the
beginning or cessation of arrival of electrons on its far side is
shorter than it would be if the electrons simply diffused across as
they do in a conventional transistor.  This entails building a more
complex structure for each transistor, and I recall/believe that more
connections are required since one must apply an accelerating voltage.

Incidentally, I don't understand why InP (indium phosphide) should be
thought superior to GaAs at this stage of development.  Both are
III-V compound semiconductors, both are therefore inherently more
difficult to work with than Si or Ge, and the fact that InP is less
well developed may simply mean we haven't seen its worst problems.

Arguments based on the toxicity of As are beside the point: fabrication
of small-scale multi-layer devices on a commercial scale seems currently
to require the use of organometallic reagents.  It seems unlikely that
any of these will be non-toxic.  For that matter, seems to me that there's
folks using phosgene as a P source for doping Si someplace on campus...


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