Structural and optical properties of Si hyperdoped with Te by ion implantation and pulsed laser annealing

Abstract

Structural and absorption properties of Te-implanted silicon layers after pulsed laser melting, equilibrium furnace annealing and rapid thermal annealing were examined and compared. The advantage of laser annealing in the formation of absorbing silicon-based layers is demonstrated. Silicon layers doped with Te up to concentrations of (3–5) × 10²⁰ cm⁻³ were formed via ion implantation and pulsed laser melting. It is found that 70–90% of the embedded impurity atoms are in substitutional states in the silicon lattice. A significant increase of the absorption (to 35–65%) in the wavelength range of 1100–2500 nm is obtained, which is useful for Si-based photodiodes. The effect of energy density of the laser pulse on the structural and optical properties of Te-hyperdoped silicon is discussed. The current-voltage characteristics and the photosensitivity of Te-doped silicon photodiodes are investigated.