F 69. The 143 Specification reports the properties of another “prior art” film –Control B– as having
a resistivity of 11,020 which increased by 130% in twenty-four hours. Application
09/128,143, Specification, p. 12, ll. 2-10 and Table III, Control.
F 70. The 143 Specification attributes instability of the resistivity to undesirable amounts of carbon
which causes the resistivity to degrade when exposed to the atmosphere:
The titanium nitride obtained contains significant amounts of carbon, and the
resultant titanium nitride films are chemically reactive. Thus when the films
are exposed to air or other oxygen containing gas, oxygen is absorbed and the
films then contain both carbon and oxygen as impurities. Since the oxygen
absorption is uncontrolled, the stability of the films is impaired, which
adversely affects the resistivity of the film in particular, in addition to possibly
impairing the reliability of devices made from the films.
Application 09/128,143, Specification, p. 7, ll. 4-13.
F 71. The 143 Specification also describes some additional unsuccessful processes (Examples C1-
C4) attempting to improve the properties of TiN CVD films. Application 09/128,143,
Specification, p. 3, ll. 2-15; p. 10, ll. 12-24.
F 72. Some of these processes were said to introduce additional gases during the CVD step.
Application 09/128,143, Specification, p. 10, ll. 12-16.
F 73. The results are summarized in Table 1. Application 09/128,143, Specification, p. 10.
F 74. Only Example C2, deposited in the presence of NF3, showed decreased resistivity compared
to the control sample. Application 09/128,143, Specification, p. 10, Table 1, Example C2.
F 75. However, Example C2 was said to be unacceptable because of high fluorine content.
Application 09/128,143, Specification, p. 10, l. 28 - p. 11, l. 3.
F 76. The other examples (C1, C3 and C4) were reported has having resistivities significantly
higher than the unacceptable resistivity of 16,000 :ohm-cm reported for the “prior art”
control. Application 09/128,143, Specification, p. 10, Table 1, Example C1, C3 and C4.
F 77. The 143 Specification also describes three additional CVD processes said to have used pre-
and post-treatments in attempting to lower resistivity. Application 09/128,143, Specification,
p. 11, ll. 4-20.
-15-
Page: Previous 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Next
Last modified: November 3, 2007