Tungsten silicide films were formed by the chemical vapor deposition method using the reaction
WF6
and
Si2H6
. The deposition rate, resistivity, composition, stress, crystal structure, and content of impurities were studied and compared with tungsten silicide films deposited by reaction of
WF6
and
SiH4
. The tungsten silicide films made using
Si2H6
have a higher deposition rate and higher Si concentration than those made by using
SiH4
at the same substrate temperature. For these reasons, the tungsten silicide films made by using
Si2H6
were found to have a resistivity that is a little higher and, after annealing, a stress that is smaller than that made by
SiH4
. Also, the resistance of tungsten silicide to peeling is larger than that of the film made by using
SiH4
. The crystal structure of the
WSix
films made by
Si2H6
is almost the same as that made by
SiH4
; however, a tetragonal
W5Si3
structure easily forms even in Si‐rich films of
WSi2.6
. Content of fluorine in films made by
Si2H6
is smaller than that in films made by
SiH4
.
It is shown that CVD tungsten silicide films prepared by reaction of WF6 and Si2H6 have a higher deposition rate and higher Si content than those obtained from WF6 and SiH4 at the same substrate temperature.
Stresses in chemical-vapor-deposited tungsten silicide and tungsten films at high temperatures were measured. Tungsten silicide films were formed from WF6 and SiH4 or Si2H6. Tungsten films were formed from WF6 and H2. The stress in tungsten silicide films is tensile and in the order of 109–1010 dynes/cm2. For a composition ratio of Si/W≤2.6, the stress of a film of more than 1000 Å has a maximum at about 500 °C. On the other hand, for a composition Si/W>2.9, the stress has no maximum. The maximum of the stress is caused by crystallization of the film. The stress has two components. One component is related to the difference of the thermal expansion coefficients between the film and the Si substrate. Another is related to the film crystallization. It was found that the stress concentrates in the portion of the film nearest the substrate. The stress in tungsten films also reaches a maximum at 550 °C, similar to the tungsten silicide films. However, the cause of this behavior is not clear.
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