MEASUREMENT OF CARRIER CONCENTRATION AT THE GAAS-SI INTERFACE IN GAASON SI BY RAMAN-SCATTERING

The free carrier concentration in GaAs-on-Si was measured by Raman sca ttering at the GaAs back face which is revealed by etching the Si subs trate. Asymmetric Raman spectra attributed to the coupled plasmon-long itudinal optical (LO) phonon mode (L+) observed in the range of 400 to 700 cm(-1) indicate that an electron concentration greater than 1.6 x 10(18) cm(-3) is induced by incorporation of Si atoms into the GaAs l ayer at the Si-GaAs interface in metal-organic chemical vapor depositi on (MOCVD) grown GaAs-on-Si's at 700 degrees C for 15 min.