Structural change of atomic-order nitride formed on Si1-xGex(100) and Ge(100) by heat treatment

Thermal stability of atomic-order nitrided Si(100), Si0.6Ge0.4(100) and Ge(100) formed in NH3 gas environment at 400 deg. C and structural change of the nitrided surface were investigated. It was found that N atom amount on Ge(100) tends to decrease at higher heat-treatment temperatures above 400 deg. C. Especially with H2 heat treatment, the N atom amount on Ge(100) becomes below detection limit for X-ray photoelectron spectroscopy measurement. On the other hand, it was confirmed that the N atom amount on Si(100) and Si0.6Ge0.4(100) is almost independent of heat-treatment conditions in the temperature range of 400-700 deg. C. From the change of chemically shifted components in Si 2p and Ge 3d spectra for Si0.6Ge0.4(100), it is suggested that N atoms bound to Ge atoms tend to be transferred to Si atoms at higher heat-treatment temperatures above 400 deg. C