Seed selection through ion channeling to modify crystallographic orientations of polycrystalline Si films on SiO2: Implant angle dependence

Abstract

Polycrystalline silicon films 4800 Å thick deposited by low pressure chemical vapor deposition at 620 °C on oxidized silicon wafers have been amorphized by implantation with 210‐keV Si²⁸ ions to a dose of 10¹⁵ cm⁻² at 0°, 1°, 3°, 5°, or 7° from normal incidence and subsequently recrystallized at 700 °C. The as‐deposited film was {110} textured with the 〈110〉 directions within ±20° of the surface normal. After the 0°, 1°, or 3° implant and subsequent recrystallization, most of the 〈110〉 directions were confined to within ±4° of the corresponding implant direction. For the 5° and 7° implants, the 〈110〉 directions in the recrystallized layers became randomly oriented; that is, the films lost their {110} texture. These results can be explained by the process of seed selection through ion channeling (SSIC): the grains that survived the 0°, 1°, or 3° implant due to ion channeling acted as seeds during <named-content xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"...