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

• Published in: Applied physics letters 1985-04, Vol.46 (7), p.683-685
• Main Authors: KUNG, K. T.-Y, IVERSON, R. B, REIF, R
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Doping and impurity implantation in iii-v and ii-vi semiconductors; Exact sciences and technology; Physics; Structure of solids and liquids; crystallography
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.95529

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 recrystallization. The fact that the direction of the 〈110〉 axes in the recrystallized films was coincident with the implant angle strongly supports the existence of the SSIC process.