OPTIMIZATION OF GROWTH-CONDITIONS FOR STRAINED SI SI1-YCY STRUCTURES/

Preparation of Si1-yCy/Si(001) and Si/Si1-xGex/Si1-yCy/Si(001) heteros tructures using molecular beam epitaxy (MBE) with C obtained from subl imation of SiC in a high-temperature cell is reported. Accumulation of surface roughness is found to occur during growth of C-rich layers ev entually leading to a reduction of the C-induced strain. The roughness can be suppressed at increased growth rates and/or decreased substrat e temperature during growth of Si1-yCy layers. Modulation of the growt h temperature has been found advantageous for optimizing both the morp hology and photoluminescence properties. Near band-edge luminescence f rom Si1-yCy/Si multiple quantum well (MQW) structures has been observe d and a conduction band edge shift equal to 63 meV/% C has been deduce d from an effective mass calculation. (C) 1998 Elsevier Science S.A. A ll rights reserved.