Synchrotron‐radiation‐induced photodoping using disilane molecular‐beam epitaxy: Low‐temperature high doping of B

Synchrotron‐radiation (SR) ‐induced doping of B has been demonstrated using disilane molecular‐beam epitaxy. By SR irradiation, B incorporation is enhanced by two to five times compared to growth without SR irradiation at 550 °C. Doped epitaxial film can be obtained using SR even at 80 °C where conventional gas‐source molecular‐beam epitaxy cannot, so far, achieve Si epitaxy. It was found that B concentration has linear dependence on the decaborane partial pressure. This suggests that the B incorporation is limited by the photolysis of decaborane and the photoinduced removal of hydrogen from adsorbed B hydrides. It was also observed that the electrical activation rate of B is enhanced by SR irradiation especially in the region where B concentration is close to the solid solubility.