GROWTH OF TERNARY ALLOY SI1-X-YGEXCY BY RAPID THERMAL CHEMICAL-VAPOR-DEPOSITION

Epitaxial layers of the ternary alloy SiGeC were grown on [100] Si sub strates. Using a rapid thermal chemical vapor deposition reactor worki ng at low temperature and reduced pressure (550 degrees C and 1 Torr), we obtained SiGeC layers with a carbon concentration into substitutio nal sites of up to 1.5%. We used two methods to measure the substituti onal C fraction in the SiGeC samples: Fourier transform infrared measu rements at room temperature and x-ray diffraction of the d(004) atomic distance in the alloys. Using methylsilane (SiH3CH3, or MS) as the ca rbon precursor, we measured an activation energy for Si0.845Ge0.15C0.0 05 growth of around 52 kcal/mol and showed that C incorporation into s ubstitutional sites saturates at high MS flows. Finally, thermal annea ling of these ternary alloys has been studied: a 800 degrees C anneali ng for 15 min leads to oxygen and carbon diffusion, whereas strain rel axation occurs by amorphous SIC precipitation with a 900 degrees C, 15 min annealing. (C) 1995 American Vacuum Society.