J. Phys. l V France 9 (1 999) Layer-by-layer growth of silicon nitride films by NH3 and SiH4

Abstract. Layer-by-layer growth of silicon nitride by NH, and SiH, was investigated using an ultraclean low-pressure CVD system with a Xe flash lamp. Thermal nitridation on Si(1OO) in an NH, environment with and without the flash lamp light irradiation is explained assuming Langmuir-type physical adsorption of NH, and reaction of the adsorbed NH,. The reaction can be enhanced by Xe flash lamp light irradiation, and the N atom concentration tends to saturate to-2.7~10'~crn-~. In Si deposition on the ultrathin silicon nitride, it is found that N desorption fiom the Si nitride films hardly occurs, and the deposited Si atom concentration increases up to about the single atomic layer concentration ( 6. 8 ~ 1 0 ' ~ ~ m- ~ ) , and then the Si deposition rate drastically increases. From FTIRIATR and RHEED measurements, the structures of the Si film on Si and the Si nitride are found to be different. Layer-by-layer growth control of Si nitride is proposed by combining atomic-layer nitridation on Si and atomic-layer growth of Si on the Si nitride. 1