Phosphorous Doping of Strain-Induced Si1-yCy Epitaxial Films Grown by Low-Temperature Chemical Vapor Deposition

Abstract

Pseudomorphic Si1-yCy alloy layers were grown on Si(001) substrates by plasma-enhanced chemical vapor deposition and mercury-sensitized photochemical vapor deposition. By depositing the films using SiH4, H2 and SiH2(CH3)2 at a very low substrate temperature of 200°C, we successfully obtained epitaxial Si1-yCy films with a high substitutional C composition of up to 3.5%. In situ P doping was carried out using PH3. Si1-yCy films required annealing to activate the P atoms. However, the measured Hall mobility of the Si1-yCy films decreased after annealing at 700°C. After thermal treatment at 900°C for 1 min, the mobility recovered to the same level as that of bulk Si and an electron concentration of about 1019 cm-3 was achieved.