CHEMICAL VAPOR DEPOSITION OF THIN FILM MATERIALS FOR ...

fixing the other conditions as follows: plasma power 100W, substrate T 250˚C, pressure 0.1 torr,
TDMAH pulse 5 s, hydrogen plasma 25s, and the purge time after hydrogen plasma is 5s, the
purging time after TDMAH pulse is adjusted. As one can see in Fig.33, with increasing purging
time from 15 to 35 s the oxygen concentration in the thin film has been reduced to around 6 at%.
Longer purging time than 35s doesn't have much effect and make the thin film growth even
slower.
Fig. 33. The effect of purging time on oxygen incorporation.
By using this purging time, other PEALD processing conditions are studied to see their
effects on thin film surface chemistry. Surface chemical compositions of thin films deposited at
different temperatures, pressures and plasma powers are listed in table 2. Apart from the desired
Table 2. In vacuo XPS results of thin film surface chemical composition at different experimental conditions.
Plasma
Power (W)
Substrate
Temperature
(˚C)
Reaction
Pressure
(torr)
Chemical composition (atom %)
Hf N C O
100 150 0.1 33.6 (±2.4) 36.1 (±2.7) 18.1 (±1.3) 12.1 (±1.5)
100 250 0.1 38.6 (±2.6) 39.4 (±2.3) 18.7 (±1.2) 3.3 (±1.0)
100 350 0.1 35.9 (±2.2) 37.6 (±2.4) 19.8 (±1.2) 6.6 (±0.9)
50 250 0.15 35.3 (±1.9) 39.9 (± 3.0) 20.8 (±2.0) 4.0 (±1.0)
100 250 0.15 30.7 (±2.2) 34.3 (±2.8) 27.5 (±1.4) 7.5 (±0.8)
150 250 0.15 34.6 (±2.7) 38.7 (±3.1) 17.6 (±1.8) 9.1 (±1.4)
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