Solid phase epitaxy of amorphous Ge films deposited by PECVD

Abstract

Amorphous thin Ge films were deposited by plasma enhanced chemical vapor deposition (PECVD) on Si(1 1 1) substrates and then annealed at 600 °C in N 2 atmosphere for 1 min. The amorphous Ge films are transformed into single crystalline Ge films by solid phase epitaxy. The influence of deposition temperature on crystalline quality, morphology, and twin density of annealed Ge films was studied. X-ray diffraction shows that after annealing the Ge films are mono-crystalline with [1 1 1] orientation parallel to the Si [1 1 1] orientation. Amorphous Ge layers were deposited at temperatures between 50 and 300 °C. Deposition at 100 °C shows the best crystal quality after annealing, with X-ray rocking curve FWHM of the (1 1 1) diffraction peak of 155 arc sec for a thickness of 53 nm. These mono-crystalline Ge films on Si(1 1 1) can be used as Ge substrate for epitaxial growth of III/V materials.