Hydrogen refinement during solid phase epitaxy of buried amorphous silicon layers

Abstract

The effect of hydrogen on the kinetics of solid phase epitaxy ͑SPE͒ have been studied in buried amorphous Si layers. The crystallization rate of the front amorphous/crystalline ͑a/c͒ interface is monitored with time resolved reflectivity. Secondary ion mass spectrometry ͑SIMS͒ is used to examine H implanted profiles at selected stages of the anneals. The H retardation of the SPE rate is determined up to a H concentration of 2.3ϫ 10 20 cm −3 where the SPE rate decreases by 80%. Numerical simulations are performed to model the H diffusion, the moving a/c interfaces and the refinement of the H profile at these interfaces. Despite the high H concentration involved, a simple Fickian diffusion model results in good agreement with the SIMS data. The segregation coefficient is estimated to be 0.07 at 575°C. A significant fraction of the H escapes from the a-Si layer during SPE especially once the two a/c interfaces meet which is signified by the lack of H-related voids after a subsequent high temperature anneal.

Two- and Three-Dimensional Recrystallization of Discrete Amorphous in C3H5-Molecular-Ion-Implanted Silicon Surface Analyzed by TCAD Simulation

“…Several previous papers reported that carbon and hydrogen with percentage-order concentrations decrease the velocity of SPEG. [28][29][30][31][32] k B is the Boltzmann constant, and T is the absolute temperature in the subsequent thermal annealing treatment. The parameters used for MC ion implantation and KMC recrystallization simulation are summarized in Table I.…”

Hydrogen kinetics in a-Si:H and a-SiC:H thin films investigated by real-time ERD

“…It is thus of technological importance that not only the H content is accurately determined in the material but also its depth distribution and kinetic properties be established. For low H concentrations, H diffusion is often determined by secondary ion mass spectroscopy [4]. In a-Si:H and a-Si 1-x C x :H, Fourier transform infrared spectroscopy is widely used to quantify and assign IR active vibrations bonds.…”