Ion Implantation as a Tool for Controlled Modification of Photoelectrical Properties of Silicon

Abstract

The results of our recent studies of controlled modifications of the photoelectrical properties of n-Si due to B + ion implantation are supplemented with new data, summarized and analyzed. The starting material was wafers of single-crystalline n-Si and a silicon-on-insulator structures. p-n-Si structures were fabricated by ion implantation of B + in doses ranging from 1 × 10 13 to 1 × 10 15 сm −2 and ion acceleration energies of 50 and 32 keV. Subsequent annealing was performed both by steady-state (900 and 1000°C, 20 min) and pulsed photon processing. In such structures, a pronounced photosensitivity is observed in the short-wave infrared range (1.5–2.2 μm), as well as in the ultraviolet region within 0.25–0.40 μm. A well-defined correlation between the structural, electrical and photoelectrical properties and the implantation and annealing regimes, as well as the content of C and O impurities is demonstrated. In the starting material, a damaged layer with a thickness of hundreds of nanometers was found to have a significant effect on the results obtained. The main results are discussed in terms of the formation/transforma-tion of deep-level extended defects in n-Si during B + implantation followed by annealing. Innovative application approaches of the technology are obvious.