Control method and system for use when growing thin-films on semiconductor-based materials

A process for controlling the growth of a thin film upon the surface of a substrate involving the exposure of the substrate surface to vaporized material in a high vacuum (HV) facility in multiple growth stages, the process including the steps of:

• (a) exposing the surface of the substrate to vaporized material during one growth stage of the build up of the thin film upon the substrate surface;
• (b) directing an electron beam in a computer-controlled process toward the surface of the substrate as the substrate surface is exposed to the vaporized material so that electrons are diffracted from the substrate surface;
• (c) monitoring the pattern of electrons diffracted from the substrate surface as the vaporized material settles upon the substrate surface including the steps of providing a programmed and computer-stored target pattern of diffraction wherein the target pattern corresponds to the pattern of diffraction indicative of the desired condition of one stage of the thin film being grown upon the substrate and wherein the monitoring step is sensitive to within 0.07 of a monolayer of the film and continually comparing the monitored pattern to the target pattern as the vaporized material settles upon the substrate surface;
• (d) automatically shutting off or otherwise adjusting the exposure of the substrate to the vaporized material when the monitored pattern matches the target pattern indicative of the desired condition of said one stage of the thin film being grown upon the substrate;
• and
• (e) repeating steps (a) through (d) during another growth stage of the build up of the thin film upon the substrate surface and so that the exposure of the substrate to the vaporized materials in the repeated step (d) is shut off or otherwise adjusted when the monitored pattern achieves a programmed and computer-stored target pattern indicative of the desired condition of said another growth stage of the thin film being grown upon the substrate.

In a process for growing or controlling the growth of a thin film of an alkaline earth oxide upon the surface of a semiconductor-based substrate involving the exposure of a surface of the semiconductor-based substrate to atoms of alkaline earth metal and oxygen in a high vacuum environment, the improvement comprising the steps of:

• exposing the surface of the semiconductor-based substrate to atoms of the alkaline earth metal following the development of high vacuum conditions about the semiconductor-based substrate but before the surface of the semiconductor-based substrate is exposed to both alkaline earth metal atoms and oxygen atoms so that only atoms of the alkaline earth metal come to rest upon the surface of the substrate;
• directing a beam in a computer-controlled process toward the surface of the substrate as the substrate is exposed to the atoms of the alkaline earth metal to effect diffraction from the substrate surface by the beam;
• monitoring the diffraction pattern of the substrate surface as the atoms of the alkaline earth metal settle upon the substrate surface including the steps of providing a programmed and computer-stored target pattern of diffraction wherein the target pattern corresponds to the pattern of diffraction indicative of a preselected fraction of a monolayer of the alkaline earth metal being grown and wherein the monitoring step is sensitive to within 0.07 of a monolayer of the film and continually comparing the monitored pattern to the target pattern as the atoms of the alkaline earth metal settles upon the substrate surface;
• automatically shutting off the exposure of the substrate to the atoms of alkaline earth metal when the monitored pattern matches the target pattern.

In a process for growing or controlling the growth of a thin film whose structure is designated as A′BO3 upon one of an AO or a BO3 truncated perovskite surface wherein each unit cell of the A′BO3 structure is comprised of a single plane of alkaline earth oxide (AeO) and a single plane of a transition metal oxide (TmO) and wherein the growth process involves the exposure of an AO or a BO2 truncated perovskite surface alternatively to atoms of the AeO plane and to atoms of the TmO plane during the build-up of the thin film one single plane layer-at-a-time in a high vacuum environment, the improvement comprising the steps of:

• directing a beam in a computer-controlled process toward the AO or BO2 truncated perovskite surface as the AO or BO2 truncated surface is exposed to either the atoms of the Aeo plane or the atoms of the TmO plane to effect diffraction from the AO or BO2 surface by the beam;
• monitoring the diffraction pattern of the AO surface as the corresponding atoms settle upon the AO surface in a build-up process including the steps of providing a programmed and computer-stored target pattern of diffraction wherein the target pattern corresponds to the pattern of diffraction indicative of the desired condition of the film being grown and wherein the monitoring step is sensitive to within 0.07 of a monolayer and continually comparing the monitored pattern to the target pattern as the vaporized material settles upon the substrate surface;
• and
• automatically halting or adjusting the deposition process when the monitored pattern matches the target pattern.