Formation of polycrystalline SiGe thin films by the RF magnetron sputtering method with Ar–H2 mixture gases

Polycrystalline silicon–germanium (SiGe) films were prepared on corning ♯7059 substrates by an RF magnetron sputtering method. The crystallization temperature of SiGe films could be decreased from 600 to 400 °C due to the introduction of H2 into the sputtering gases probably because of the enhancement of the surface reaction caused by the hydrogen radicals. The optical absorption coefficients of SiGe films by the Ar–H2 gas sputtering are similar to those of the single crystalline SiGe, nevertheless much higher values are observed in SiGe films by the Ar sputtering. The dark conductivity of the films decreases from 1.2×10−2 to 2.1×10−6 S/cm, and their properties seem closer to the intrinsic properties with the introduction of H2. These results suggest that the introduction of H2 into the sputtering gases is effective to decrease the crystallization temperature and to improve the optical and electrical properties of SiGe films.