Dynamics of metal-induced crystallization of ultrathin Ge films by rapid thermal annealing

Yuanxun Liao, Shujuan Huang, Santosh Shrestha, Gavin Conibeer

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Though Ge crystallization has been widely studied, few works investigate metal-induced crystallization of ultrathin Ge films. For 2 nm Ge films in oxide matrix, crystallization becomes challenging due to easy oxidation and low mobility of Ge atoms. Introducing metal atoms may alleviate these problems, but the functions and the behaviours of metal atoms need to be clarified. This paper investigates the crystallization dynamics of a multilayer structure 1.9 nm Ge/0.5 nm Al/1.5 nm Al2O3 under rapid thermal annealing (RTA). The functions of metal atoms, like effective anti-oxidation, downshifting Raman peaks, and incapability to decrease crystallization temperature, are found and explained. The metal behaviours, such as inter-diffusion and defect generation, are supported with direct evidences, Al-Ge nanobicrystals, and Al cluster in Ge atoms. With these understandings, a two-step RTA process achieves high-quality 2 nm nanocrystal Ge films with Raman peak at 298 cm-1 of FWHM 10.3 cm-1 and atomic smooth interfaces.

Original languageEnglish
Article number232106
Pages (from-to)1-5
Number of pages5
JournalApplied Physics Letters
Volume107
Issue number23
DOIs
Publication statusPublished - 7 Dec 2015
Externally publishedYes

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