Appeal 2006-2769
Application 09/846,980
using a reflective electron beam, where this irradiation changed
the p-layer into a p-type conductive semiconductor with a hole
concentration of 5 x 1017/cm3, 5 x 1017/cm3 and 2 x 1017/cm3
and a resistivity of 0.5 ohm-cm, 0.8 ohm-cm and 1.5 ohm-cm,
respectively (col 5, In [sic, ll.] 14-26). Koike et al also teaches
forming metal electrode, such as nickel or aluminum, are
formed on semiconductor devices utilizing GaN group
compounds such as A1GaInN after the semiconductor surface
is cleaned by wet chemical etching, utilizing a wet chemical
etchant such as buffered hydrogen fluoride (col 1, In [sic, ll.]
15-30).
It would have been obvious to a person of ordinary skill
in the art at the time of the invention to modify Bour with
Koike's electron beam irradiation because it would have
produced p-type conductive semiconductors with low
resistivities.
3. The Appellants only argue that the prior art references would not have
suggested “heating said p-type layer to a third temperature greater than the
second temperature and less than 625oC to remove hydrogen from said p-
type layer…” recited in claims 1 and 31.
4. Bour teaches (col. 6, ll. 46-58) that:
Upon attainment of this temperature [around 600o C. to 800o
C.], the N outdiffusion preventor gas, NH3, is switched out of
reactor 10, as shown in step 35 in FIG. 6, and acceptor
activation is performed either as the reactor is further cooled
down or at a temperature maintained for a given period of time
as indicated at step 36. As an example, if the temperature is
maintained at 600º C., then the time period for activation may
be tens of minutes, such as, for example, between about 20 to
about 40 minutes. This anneal process indicated in FIG. 3
wherein, during the cooldown of reactor 10, a flow of molecular
N, N2, is maintained in the reactor as acceptor activation is
carried out in the matter as just described.
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