Ultralow temperature epitaxial growth of silicon-germanium thin films on Si(001) using GeF4

• Si2H6 and GeF4 are used as source gases.
• The temperature dependence of growth kinetics has been investigated.
• High quality Si1 − xGex (x = 0.99) has been prepared directly on Si wafer at 300 °C.
• For 300 nm-thick film, a TDD of ~ 2 × 107 cm− 2 and RMS roughness of 0.8 nm are achieved.

By designing oxidation-reduction reaction, epitaxial growth of silicon-germanium (Si1 − xGex: 0 ≤ x ≤ 1) films on Si(001) at low temperature has been achieved using reactive thermal CVD (RTCVD). Si2H6 and GeF4 are used as source gases. The temperature dependence of growth kinetics has been investigated. The results indicate that films grown at high temperature tend to be polycrystalline; on the contrary, a lower temperature promotes the selective growth and surface reaction assists the improvement of the crystal quality. High quality Si1 − xGex (x = 0.99) has been prepared directly on Si wafer at 300 °C with the RMS roughness of 0.8 nm and threading dislocation density of 2 × 107 cm− 2.

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