Early Stage of Polycrystalleve Growth of Ge and SiGe by Reactive Thermal Cvd from GeF4 and Si2H6

Abstract

ABSTRACTWe have investigated the structure and crystallinity of poly SiGe and Ge films in the early stage of their growth prepared at < 450°C by means of a new type of thermal CVD from GeF4 and Si2H6. Raman study and SEM observation of the films revealed that the nucleation of crystallites took place directly on the substrate, followed by the grain growth in a manner of island growth. Thus, the crystallinity of the films is well established even in the very early stage of the growth, probably < 10 nm in thickness, in contrast to the poly Si growth in the low-temperature CVD precesses.