OPTICAL STUDY OF APCVD-GROWN SI1-XGEX SI QUANTUM-WELL STRUCTURES UNDER DIFFERENT POSTGROWTH ANNEALING CONDITIONS/

Single and double Si1-xGex/Si quantum well (QW) structures, which were grown by atmospheric pressure chemical vapor deposition (APCVD). are characterized by photoluminescence and secondary-ion mass spectrometry . Systematic post-growth annealing treatments are carried out at tempe ratures between 600 and 1100 degrees C in pure N-2 ambient. The interd iffusion between the Si layer and the S1-xGex well layers occurs at th e annealing temperature around 900 degrees C. From SIMS measurements f or single QW structures we have estimated the activation energy which is about 3.9 eV in the temperature range between 950 degrees C and 110 0 degrees C. The double QW structures show a similar value. The intens ity of the exciton recombination related to carriers confined in the d ouble QW structures decreases with increasing annealing temperatures a nd becomes strongly suppressed at 750 degrees C. When the annealing te mperature is increased further, the intensity of the QW emission recov ers in the QW structures. (C) 1998 Published by Elsevier Science B.V. All rights reserved.