Integral stress in ion-implanted silicon

Abstract

A theoretical model of production and relaxation of stress in ion-implanted silicon is proposed. It is based on the assumptions that the point defects are the source of mechanical stress and that the relaxation of stress is due to the viscous flow of ion-irradiated silicon. The integrated stress acting in a damaged layer has been studied as a function of the -ion current density j = 0.01-, ion energy -160 keV, substrate temperature T = 78-500 K and dose in the range up to . It was shown that the maximum integral stress values induced in silicon are of the order of 100 N . The maximum is reached at a dose of about that corresponds to the silicon-amorphization dose. Stress due to implanted ions is essential for the high-dose region and it dominates at high temperatures of the substrate.

Effects of dopant type and concentration on the femtosecond laser ablation threshold and incubation behaviour of silicon

“…Their study however, only reached a maximum of 1000 pulses, compared to the ~30,000 pulses maximum studied here, which may not have been sufficient to reach the constant value of the infinite pulse ablation threshold (Fth,∞). We hypothesise that this steady state is reached due to the high concentration of laser-induced defects, leading to mechanical stresses within the solid which increase the energy barrier for formation of new defects [37]. The infinite pulse ablation threshold (Fth,∞) thus corresponds to the pulse fluence that is no longer able to overcome this energy barrier and increase the defect concentration.…”

Amorphization and stress in ion-implanted crystalline solids

“…Following the model of stress formation described in [18][19][20][21], we assume that the strain in the ion-implanted surface layer is due to the point defects, which correspond to the "displaced atom plus vacancy node" pairs. Let us denote the relative increment of the atomic volume due to the "vacancies" and displaced atoms as ∆Ω v /Ω and ∆Ω s /Ω, respectively, and the relative volume increment due to the implanted ions as ∆Ω ion /Ω.…”

The effect of nitrogen ion implantation on wear behaviour of single-crystal SiO2

“…Previous investigations have shown that ceramic samples modified by ion implantation can reduce the wear, albeit with the friction coefficient remaining quite large [4][5][6]. Most of the studies in this field have been focused on Al 2 O 3 , MgO, Si, SiC and Si 3 N 4 [7][8][9][10][11][12], relatively little work has dealt with the ion implantation into SiO 2 . In this paper, the effect of nitrogen ion implantation on the wear behaviour and the change of structure of single-crystal SiO 2 was investigated by SEM, TEM and XPS.…”