MeV-energy As+ implantation into Si: Extended-defect reduction and planar n-p-n transistor fabrication

Abstract
With 2.5 MeV‐As+ implantation into Si, etch‐pit density (after annealing) could be lowered below 104 cm2, whether D was smaller than 5×104 or larger than 2×102. Here D stands for damage degree in the as‐implanted sample [0(single‐crystalline)≤D≤1 (amorphous)]. At given doses, D could be controlled to be at its optimal value by wafer temperature (over a range from 25–300 °C). By utilizing such MeV‐energy implantation to form buried collector layers, planar npn transistors could be successfully fabricated even without epitaxial growth.