Evidence for the formation of SiGe nanoparticles in Ge-implanted Si3N4

Abstract

SiGe nanoparticles were formed in an amorphous Si 3 N 4 matrix by Ge þ ion implantation and thermal annealing. The size of the nanoparticles was determined by transmission electron microscopy and their atomic structure by x-ray absorption spectroscopy. Nanoparticles were observed for excess Ge concentrations in the range from 9 to 12 at. % after annealing at temperatures in the range from 700 to 900 C. The average nanoparticle size increased with excess Ge concentration and annealing temperature and varied from an average diameter of 1.8 6 0.2 nm for the lowest concentration and annealing temperature to 3.2 6 0.5 nm for the highest concentration and annealing temperature. Our study demonstrates that the structural properties of embedded SiGe nanoparticles in amorphous Si 3 N 4 are sensitive to the implantation and post implantation conditions. Furthermore, we demonstrate that ion implantation is a novel pathway to fabricate and control the SiGe nanoparticle structure and potentially useful for future optoelectronic device applications. Published by AIP Publishing.

Enhancing Short-Wave Infrared Photosensitivity of SiGe Nanocrystals-Based Films through Embedding Matrix-Induced Passivation, Stress, and Nanocrystallization

“…This leads to the formation of small SiGe NPs with average size of 1.8 nm (2.2 nm) increasing to 2.8 nm (3.2 nm) with the increase of the ion fluence and implanted Ge concentration for 700 °C (900 °C) annealing, NPs having dominant disordered crystalline structure. It was argued that Ge atoms have low diffusivity in Si 3 N 4 and that the LPCVD Si 3 N 4 layer has a “rigid structure” . This is reflected in the depth distribution of Ge atoms before and after annealing that shows no significant loss or redistribution of Ge atoms after thermal annealing.…”

“…34 SiGe NPs formation in amorphous Si 3 N 4 matrix was evidenced by Ge + ion implantation into thick amorphous Si 3 N 4 layers deposited by LPCVD on Si substrates maintained at 400 °C followed by thermal annealing for 1 h at 700 or 900 °C. 74 This leads to the formation of small SiGe NPs with average size of 1.8 nm (2.2 nm) increasing to 2.8 nm (3.2 nm) with the increase of the ion fluence and implanted Ge concentration for 700 °C (900 °C) annealing, NPs having dominant disordered crystalline structure. It was argued that Ge atoms have low diffusivity in Si 3 N 4 and that the LPCVD Si 3 N 4 layer has a "rigid structure".…”

“…It was argued that Ge atoms have low diffusivity in Si 3 N 4 and that the LPCVD Si 3 N 4 layer has a "rigid structure". 74 This is reflected in the depth distribution of Ge atoms before and after annealing that shows no significant loss or redistribution of Ge atoms after thermal annealing.…”