Molecular beam epitaxy of GaP films on Si substrates

Molecular beam epitaxy (MBE) of GaP films on Si substrates was developed because this structure has possibilities to realize GaP/Si based high efficiency (about 36 percent) tandem solar cell and also GaP/Si based optoelectronic ICs. A low temperature Si surface celaning method at a temperature as low as 800 C was established. Single-crystalline GaP films were successfully grown on Si(001) substrates in a wide growth temperature range from 300 to 600 C. During the film growth, Sn and Si were doped for n-type dopants and Be was doped for p-types. Also Zn-O complexes which act as radiative recombination centers were successfully doped during the growth of GaP films. Process compatibility of Si device process and GaP device process was shown by a fabrication of optoelectronic ICs which integrate GaP LEDs and Si MOSFETs.