Thin film forming device for forming silicon thin film having crystallinity

In this example, the device shown in FIG. 1 was used, and a thin film of silicon was formed on the base material 10 under the following conditions:

Frequency of high frequency electric power: 60 MHz

Introduced raw material gas: SiH.sub.4 (50%) / H.sub.2, 10 sccm

Introduced inert gas: Ar 5 sccm

Pressure in plasma chamber container: 1.times.10.sup.-4 Torr

Voltage of positive polarity portion of pulse voltage: 500 V

Voltage of negative polarity portion of pulse voltage: 100 V

Frequency of pulse voltage: 500 Hz

Duty ratio of pulse voltage: 50%

Base material: Non-alkali glass base plate or silicon base plate of face (100)

Base material temperature 400.degree. C.

Film thickness: 100 nm

As a comparative example, the conventional device shown in FIG. 5 was used, and a thin film was formed under the conditions listed above except for the impression of pulse voltage. One evaluation was conducted as follows. Concentration of hydrogen contained in a thin film of silicon formed on a silicon base plate was mea...