Memory Effect in RTCVD Epitaxy of Si and SiGe

Abstract

AbstractIn the paper presented the memory effect of boron (B), phosphorus (P), and germanium (Ge) have been studied during the chemical vapor deposition of homoepitaxial Sifilms and heteroepitaxial SiGe- layers in different RTCVD equipment. The CVDprocesses were controlled by surface kinetics on Si substrates from H2, SiH4, GeH4, PH3, and B2H6 at the pressure of 2 mbar in the temperature range of 500°cC–700°C. T1e aufodoping effect from the wafer has been separated from the loading effect of the reactor. The memory effect has been shown to be small for Ge in Si and for B in Si and SiGe. However, a remarkable high memory effect has been found for P, especially in SiGe-films. There are different methods reducing the memory effect in RTCVD-reactors. In-situ gas phase etching by HCI or NF3 gives the best results in the reactors studied here. Based on the obtained results the opportunities and limitations of integrated processing of different Si and SiGe-films (e.g. complete stacks for Si/SiGe-HBT) in the same reaction chamber have been discussed.