Suppressing the cellular breakdown in silicon supersaturated with titanium

TL;DR

This paper investigates methods to suppress cellular breakdown in titanium-hyperdoped silicon during recrystallization, demonstrating that flash lamp annealing effectively prevents cellular breakdown compared to liquid phase epitaxy.

Contribution

It introduces a comparison between liquid phase and solid phase epitaxy for hyperdoped silicon, showing solid phase epitaxy suppresses cellular breakdown during recrystallization.

Findings

Cellular breakdown occurs during liquid phase epitaxy due to constitutional supercooling.

Solid phase epitaxy during flash lamp annealing suppresses cellular breakdown.

High interface velocity and low Ti diffusion in solid phase prevent cellular breakdown.

Abstract

Hyper doping Si with up to 6 at.% Ti in solid solution was performed by ion implantation followed by pulsed laser annealing and flash lamp annealing. In both cases, the implanted Si layer can be well recrystallized by liquid phase epitaxy and solid phase epitaxy, respectively. Cross-sectional transmission electron microscopy of Ti-implanted Si after liquid phase epitaxy shows the so-called growth interface breakdown or cellular breakdown owing to the occurrence of constitutional supercooling in the melt. The appearance of cellular breakdown prevents further recrystallization. However, the out-diffusion and cellular breakdown can be effectively suppressed by solid phase epitaxy during flash lamp annealing due to the high velocity of amorphous-crystalline interface and the low diffusion velocity for Ti in the solid phase.