Appeal No. 2000-0733
Application No. 08/310,041
Turning, first, to the rejection of claim 38 under 35 U.S.C. § 103, we will
summarily reverse this rejection as failing to present a prima facie case of obviousness.
The claim is directed to a method of decreasing the turn-off time of an MCT. The
examiner relies on APA for the teaching of suppressing activation of the parasitic
bipolar transistor in FETs, IGBTs and MCTs with a P-type body region having a channel
region adjacent a gate oxide layer substantially as claimed. However, as appellants
point out, at page 6 of the principal brief, “with respect to MCTs, the applicant stated
just to the contrary and asserted that such a structure was neither known or desired in
MCTs because of the fundamental difference between MCTs and IGBTS or FETs.
(See page 15, line 22 to page 18, line 19 of the specification).”
Our review of the cited portion of the specification would appear to support
appellants’ position that there is no admission of the claimed method with regard to
MCTs being known in the art. Moreover, the examiner fails to rebut appellants’
position, stating only, at page 3 of the answer, that the examiner does not rely on this
portion of the specification for APA. While that may be the case, page 15 of the
specification clearly notes that it was appellants who discovered an unknown effect of
the parasitic NPN bipolar transistor which is introduced into a thyristor when a MOS
controlled channel is introduced to control turn-off of the thyristor and thereby provide
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