Appeal No. 95-5110
Application 07/918,954
shown in Tsuzuki's Figure 1 because the distance between the n
type layer and the bottom of the trench depends upon the depth
of the trench and the breakdown voltage of the device.
Appellants argue on pages 3-5 of the brief that one of
ordinary skill in the art would not have a reason to use the
Katou trench in the Tsuzuki transistor because Tsuzuki is
concerned with providing an arbitrary avalanche breakdown
voltage at the bottom of the deep body P region in order to
prevent punch-through while in contrast Katou is concerned
with decreasing the concentration of an electric field and
increasing dielectric resistance. Furthermore, on pages 2 and
3 of the reply brief, Appellants argue that the Examiner has
failed to show a suggestion or reason that if the trench was
employed in the Tsuzuki transistor that the trench would only
extend into the N- region 4.
Upon a closer reading of the reference, we fail to find
that the prior art provides any evidence that suggests the
Examiner's modification. The Federal Circuit states that
"[t]he mere fact that the prior art may be modified in the
manner suggested by the Examiner does not make the
modification obvious unless the prior art suggested the
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