Direct nucleation of crystalline SiGe on substrates by reactive thermal CVD with Si{sub 2}H{sub 6} and GeF{sub 4}

Conference · Tue Jul 01 04:00:00 EDT 1997

OSTI ID:20085505

Yoshizawa, Fumio; Shiota, Kunihiro; Inoue, Daisuke; Hanna, Junichi

Polycrystalline SiGe (poly-SiGe) film growth by reactive thermal CVD with a gaseous mixture of Si{sub 2}H{sub 6} and GeF{sub 4} was investigated on various substrates such as Al, Cr, Pt, Si, ITO, ZnO and thermally grown SiO{sub 2}. In Ge-rich film growth, SEM observation in the early stage of the film growth revealed that direct nucleation of crystallites took place on the substrates. The nucleation was governed by two different mechanisms: one was a heterogeneous nucleation on the surface and the other was a homogeneous nucleation in the gas phase. In the former case, the selective nucleation was observed at temperatures lower than 400 C on metal substrates and Si, where the activation of adsorbed GeF{sub 4} on the surface played a major role for the nuclei formation, leading to the selective film growth. On the other hand, the direct nucleation did not always take place in Si-rich film growth irrespective of the substrates and depended on the growth rate. In a growth rate of 3.6nm/min, the high crystallinity of poly-Si{sub 0.95}Ge{sub 0.05} in a 220nm-thick film was achieved at 450 C due to the no initial deposition of amorphous tissue on SiO{sub 2} substrates.

• Research Organization: Tokyo Inst. of Tech., Yokohama (JP)
• OSTI ID: 20085505
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL VAPOR DEPOSITION
CRYSTAL GROWTH
GERMANIUM SILICIDES
MICROSTRUCTURE
NUCLEATION
POLYCRYSTALS