Appeal No. 2003-1208
Application 09/590,805
The examiner argues (answer, page 9):
Tursky et al. teach forming a first device with a field
oxide that has been implanted with a material that
traps positive charge when the first device is exposed
to ionizing radiation and the second device has not
been implanted with the material (column 9, lines 31-
51). It would have been obvious to a person of
ordinary skill in the art at the time the invention was
made to form a first device with a field oxide that has
been implanted with a material that traps positive
charge in prior art’s device, in order to obtain a soft
diode with a well known alternative method.
The portion of Tursky relied upon by the examiner teaches that
the diode soft recovery behavior can be obtained by irradiation
with protons. This portion does not, however, say anything about
field oxide or ionizing radiation. Nor does it disclose that the
protons trap positive charge, and the examiner has not provided
evidence or technical reasoning which shows that the protons trap
positive charge. Also, the examiner has not established that
this portion of Tursky would have indicated, to one of ordinary
skill in the art, a correlation between soft recovery behavior of
a diode and resistance of a transistor to ionizing radiation.
Moreover, even if Tursky’s protons trap positive charge, the
examiner has not explained why one of ordinary skill in the art
would have been led by the applied prior art to substitute those
protons for Kalnitsky’s silicon ions that trap negative charge
rather than positive charge (col. 2, line 67 - col. 3, line 3).
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