Avalanche effects in solid-phase epitaxial crystallization induced by light-ion irradiation

TL;DR

This study investigates how light-ion irradiation induces solid-phase epitaxial crystallization in amorphous silicon layers, revealing low activation energy and a shock-like process driving crystal growth.

Contribution

It provides new insights into the mechanisms of ion-induced crystallization, highlighting the role of interstitial defects and proposing a shock-like nucleation process.

Findings

Crystallization occurs at all temperatures studied.

Activation energy for regrowth is 0.07 eV.

Large prefactor indicates extensive interstitial involvement.

Abstract

Solid-phase epitaxial crystallization of amorphous Si layers on a crystalline Si substrate during B-ion irradiation is investigated over the temperature range 293 - 573 K. Regrowth occurs at all measured temperatures, with activation energy 0.07 eV and prefactor 2.36 nm / 10^14 B cm-2 The low activation energy suggests that free interstitial point defects are involved and the unusually large prefactor indicates that each interstitial crystallizes about 50 host Si atoms. We propose that interstitial annihilation at the a/c interface sets off a shock-like process that drives c-Si island nucleation and growth until terminated by misfit strain.