Diffusion processes in germanium and silicon films grown on Si3N4 substrates

In this article, the results of investigation of processes occurring during the molecular-beam deposition of germanium layers on Si3N4 dielectric substrates within a wide range of the Ge film growth temperatures (30-600 degrees C) are presented. The intensity of the IR absorption bands related to the vibrations of the N-H and Si-N bonds are established to decrease with the increase of the Ge deposition temperature. This phenomenon apparently cannot be explained as only a thermally activated process. Simultaneously, the peaks corresponding to the Ge-N and Ge-O vibration bonds emerge in the X-ray photoelectron spectra. We believe that the deposition of Ge films on Si3N4 dielectric substrates containing hydrogen atoms resulted in the migration of hydrogen atoms from the dielectric layer into the growing film. We interpret the experimental results in terms of a model, according to which the diffusion of hydrogen atoms from the Si3N4 layer into the growing Ge film occurs due to the difference in chemical potentials of hydrogen atoms in the dielectric layer and the germanium film. This process initiates the diffusion of germanium atoms in the opposite direction, into the Si3N4 layer, where they connect to dangling bonds of nitrogen atoms arising due to the escape of hydrogen atoms. The analogous processes occur during the deposition of silicon layers on Si3N4 substrates.

Automated summary

The article investigates the processes occurring during the molecular-beam deposition of germanium layers on Si3N4 dielectric substrates within a wide range of temperatures. It is found that IR absorption bands related to vibrations of N-H and Si-N bonds decrease with increasing Ge deposition temperature, while peaks corresponding to Ge-N and Ge-O vibration bonds emerge in X-ray photoelectron spectra. Experimental results suggest diffusion of hydrogen atoms from the Si3N4 layer into the growing Ge film, triggering diffusion of germanium atoms in the opposite direction.