Defect Formation in Ion-Implanted Si - Approach to Controlled Semiconductor Optical Properties

Abstract

For specific modification of the fundamental optical and photoelectrical properties of silicon transparent for wavelengths beyond 1.1μm, boron ions have been implanted into n-type wafers at doses of 1 х 1013 cm-2–1 х 1015 cm-2 followed by annealing at 900 °C and 1000 °C (20 min). The IR reflection spectra, Raman spectroscopy and scanning electron microscopy data have been compared with the photosensitivity spectra (1.4–2.2 μm) and with the integrated photoresponse in the IR (1.0–4.1 μm) and UV (0.25–0.4 μm) regions. These studies allow for materials engineering to obtain new data on the influence of defect formation on the optical properties of the material and to evaluate the technological conditions for practical application of the modified material.

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

“…In comparison with the starting material, the maximum of the band for 1×10 сm −2 is shifted towards higher values (520.2 сm −1 ), the intensity becomes twice as much, and the half-width decreases (qualitatively, the same pattern is observed for 1 x 10 14 сm −2 (annealing at 900°C). Increasing the II dose up to 1×10 15 сm −2 and annealing at 1000°C shifts the band towards smaller wave number values, the intensity decreases, and the half-width increases [19,21]. Figure 3 demonstrates a typical example of SEM measurements for starting n-Si and p-n-Si(B) annealed at 900 and 1000°С.…”

“…The carrier concentration in р-Si is estimated to be of 2 × 10 19 cm −3 . After implantation and annealing an increase in the band intensity of the Si-O oscillations (1082 cm −1 ) is observed [19,21]. Figures 7-13 show the photosensitivity spectra obtained from several samples (Si70, Si10, and SOI) under different conditions of II, annealing, and ion acceleration energies.…”

“…From Figure 7 it is obvious that the photosensitivity increases for implantation doses of up 6 × 10 14 сm −2 and then decreases for higher doses. All short-wave infrared (SWIR) spectra exhibit the main maximum corresponding with the wavelength of about 1.8 μm (0.69 eV) and a less pronounced (smoothed) maximum at approximately 1.9 μm (0.65 eV) [20][21][22]. Figure 8 illustrates an example of the photosensitivity spectra of p-n-Si(B) in the range of 1.5-2.4 μm at 300 K and 77 K for a dose of 8 × 10 14 сm −2 and annealing at 900°C (20 min).…”

“…In was shown [21,22] that in the starting material as well as in n-Si annealed up to 900 and 1000°C or B + implanted without annealing only silicon is detected within the SEM sensitivity Figure 15b shows the dependencies of the integrated photosensitivity on similar technological conditions.…”

“…In this article we summarize the results of our studies of the structural, electrical, and photoelectrical properties of p-n-Si(B).The extensive experimental material described earlier [17][18][19][20][21][22] is supplemented with new data and findings.…”