Appeal No. 1997-3512 Page 8
Application No. 08/482,034
“accelerating field acts to sweep electrons from
layer 13 to layer 12.” See col. 4, lines 50-58.
Gaw goes on to say that “the magnitude of the
accelerating field is a function of doping
concentration differential and band gap differential
between layer 12 and layer 13.” To overcome this
deficiency of Gaw, the Examiner refers to col. 3,
lines 49-51, where Gaw states that layer 12 consists
of a GaAs layer having a doping concentration
“selected to meet desired device characteristics.”
But Gaw does not teach or suggest any desired device
characteristics other than for the highly doped
“p++” layer over the lighter-doped “p” layer.
Absent any other teaching or suggestion, Gaw’s
comment concerning “desired device characteristics”
is empty of meaning. Put differently, the
accelerating field is the entire gist of Gaw’s
teaching, and its existence depends on the doping
concentration differential. Therefore, one skilled
in the art would not be motivated by Gaw to practice
the invention described in Claim 17, which involves
layers of approximately the same doping
concentration. Indeed, the skilled artisan would be
taught away from such a structure.
We are in agreement with appellants that Gaw does not
teach or suggest any desired device characteristics other than
the highly doped “p++” layer on top of the lighter doped “p”
layer and that a skilled artisan would be taught away from
making the two base layers with approximately the same doping
concentration. Merely stating that the doping concentration
of a layer may be selected to meet desired device
characteristics is not sufficient to suggest a specific doping
concentration that is contrary to the express teaching of the
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 Next
Last modified: November 3, 2007