Solid-State Electronics, Vol.60, No.1, 13-17, 2011
Solid-phase epitaxy of amorphous silicon films by in situ postannealing using RPCVD
Solid-phase epitaxy (SPE) of in situ As-doped amorphous Si (a-Si) deposited on SiO2/Si3N4 patterned Si (1 0 0) wafers by reduced pressure chemical vapour deposition (RPCVD) using a H-2-Si2H6 gas system was investigated. The SPE was performed by applying in situ postannealing directly after deposition process. On the one hand, we studied the lateral SPE (L-SPE) length of As-doped Si on mask and their crystal quality by TEM/SEM characterisation for various postannealing temperatures (700-1000 degrees C for 60 s). We observed increase in L-SPE growth and decrease of dislocation density for higher postannealing temperatures. On the other hand, L-SPE length was also investigated for different postannealing times (0-120 min at 575 degrees C) and As concentrations. At these conditions the L-SPE length has increased with increasing postannealing time. For both, higher and lower annealing temperature region, crystallization has been inhibited for higher As concentrations. After modifying As-doping level, we were able to crystallize up to 500 nm of a-Si on mask to epi-Si by combination of 575 degrees C and 1000 degrees C postannealing. (C) 2011 Elsevier Ltd. All rights reserved.