Appeal No. 1997-3484
Application 08/089,359
order to meet the limitations of "a first source contact
above said wide bandgap layer," "a first drain contact above
said wide bandgap layer," "a second source contact above
said wide bandgap layer," "a second drain contact above said
wide bandgap layer," and "a second gate contact to said wide
band-gap [sic] layer." The Examiner finds the region above
the p-channel region 3H to be the low-noise buffer layer
(EA2) and considers the region with the plus signs in
circles underlying the gate 12 as part of the gate contact
with electrode 12 (EA5). However, this is an unreasonable
distortion of Takikawa since gate electrode 12 is separated
from the layer 4 above region 3H by layer 5 and, thus, there
is no contact "to" this layer 4. above region 3H. The layer
5 is a potential barrier which is doped with impurities to
retain ionized charges (indicated by the plus signs in
circles) which shift the threshold voltage of the HEMT
toward negative (col. 5, line 62 to col. 6, line 2) and is
not part of the gate contact. Takikawa does not disclose "a
first gate contact to said low-noise buffer layer."
Third, claim 1 does not teach alloyed source and drain
contacts because, as noted by Appellants (Br4), Takikawa
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