Some characteristics of the crystalline-amorphous threshold point of /sup 31/P/sup +/ ion-implanted silicon substrates

During ion implantation a stage can be reached in which a continuous layer within the implanted crystal changes into amorphous material. The change begins when the implanted dose attains a certain threshold value (D/sub T/). In-situ reflectivity (R) versus dose (D) measurements, made during the implantation of /sup 31/P/sup +/ into Si single crystal substrates showing that both D/sub T/ and the work (W/sub oT/) required to induce the threshold conditions within the implanted crystal increase with the implantation energy are reported. It is also shown that the change in reflectivity Delta R/sub i/, which occurs in the dose range that contains D/sub T/, is a function of E and peaks at 140 keV, the energy at which the damaged layer becomes buried. The ratio D/sub A//D/sub T/ is found to be a decreasing function of E.<
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