Measurements of layer thicknesses and refractive indices in high-energy ion-implanted GaAs and GaP

Abstract

Near normal incidence reflection and transmission measurements of GaAs and GaP samples implanted with large doses of ∼3-MeV ions of 31P+ or 14N+ showed frequency-dependent maxima and minima in the frequency range 800≲ν≲7500 cm−1. Assuming a layer model for the implanted material and considering reflections from layers surfaces, the interference fringes are analyzed to obtain the refractive index and thickness of both the cover and buried layers and substrate. With the same layer model the changes in the GaAs reststrahlen are shown to be quantitatively compatible with the results of the fringe measurements. Annealing GaAs at temperatures ≲400 °C reduced the implantation-induced changes in the refractive index but the layer thicknesses remained constant. There was no evidence for regrowth by motion of the implant-substrate interface as has been reported for silicon crystals. The analysis of the reststrahlen data for GaP is less satisfactory since the data could not be closely fitted with any choice of parameters.

Infrared studies of isothermal annealing of ion-implanted silicon: Refractive indices, regrowth rates, and carrier profiles

“…This approach was also employed in an ellipsometry measurement of the damage profile ofP+ -implanted material where a transition layer was taken into account. 29 A third possibility for the (7 T values observed here is that the interface is not planar and that (7 T reflects the variation in depth over the area measured by the infrared beam (about 10-1 cm 2 ). While this latter effect might make some contribution, it is unlikely to be a dominant factor because both (7 T and (7 D become less than the minimum detectable value after the shortest annealing time employed.…”

Optical and Structural Characterization of Boron Implanted GaAs

“…It was demonstrated that observed interference spectra could be simulated very accurately by such models, provided that a sufficient number of features were incorporated to adequately approximate the physical situation (2,3). Such models gave good nonlinear least square theoretical fits to the measured reflection spectra for a wide range of as-implanted, as well as annealed samples (2)(3)(4)(5)(6)(7)(8).…”

“…In recent years there has been a number of investigations employing optical techniques to characterize materials which were ion implanted (2)(3)(4)(5)(6)(7)(8)(9). One of the techniques frequently used is based on interference effects observed for reflection from a crystalline sample in which a damaged layer was produced by implantation.…”

Modal method for second harmonic generation in nanostructures

“…5), where a square sine function at a spatial frequency Δk k 2ω − 2k ω 2n 2ω − n ω ω∕c is expected in the direction z of the incident plane wave [24,26]. The incident electric field is polarized along a 111 axis, and the following parameters are used: λ 2πc∕ω 5 μm, n 2 ω ε GaAs ω11.01, n 2 2ω ε GaAs 2ω 11.19 [27] and χ 2 2∕ 3 p × 370 pm∕V (for polarization along the 111 axis) [24]. The thickness of the crystal is equal to three times the coherence length L coh π∕Δk, and both faces have an anti-reflective coating at ω and 2ω, giving…”