Infrared reflection investigation of ion‐implanted and post‐implantation‐annealed epitaxially grown 6H‐SiC

Abstract

Multiple energy Al+ and C + ions were implanted into 6H-SiC at room temperature (25 • C) and elevated temperature (600 • C), respectively, followed by 1550• C annealing for 30 min. Fourier transform infrared spectroscopy was used to evaluate the optical properties in the mid-infrared range. An effective medium model, taking into account the presence of an implantation-induced amorphous phase, was developed to establish the relationship between the changes of optical properties and modification of structure.Complete amorphization in the implanted layer was evidenced for room temperature implantation but no such case occurred at elevated temperature implantation. Elimination or decrease of the amorphous phase, via 1550• C annealing, was represented by the recovery of reflectance intensity and shape. Some structural and optical parameters, such as layer thickness and phonon damping constants of the amorphized SiC, were derived from fitting to measured data. Our work demonstrated the successful application of the Lorentz-Drude oscillator model in evaluating the lattice quality of the amorphous/crystalline SiC system.

Structural and Optical Studies on Ion-implanted 6H–SiC Thin Films

“…It was reported [22] that the reflectance at the top of the reststrahlen band is sensitive to the surface condition of the SiC material/film and that a rough surface could cause the reflectance to drop from the low frequency edge to the high frequency edge. We have performed a theoretical calculation on the infrared (IR) reflectance spectra of 6H-SiC based upon the effective medium model [23]. It was indicated that the amorphization of the implanted layer is responsible for the presence of the deep reflection dip at ∼930 cm − 1 , which is exactly seen from Fig.…”

Migration behaviour of selenium implanted into polycrystalline 3C–SiC

“…10(a)), it is clear that the characteristic SiC Raman peaks (between 750 and 1000 cm -1 ) disappeared and three broad Raman bands appeared around 519, 880 and 1424 cm -1 . These broad bands are caused by the vibrations of Si-Si, Si-C and C-C bonds, respectively [19]. This change in the spectrum indicates that the SiC layer is amorphized as a result of the implantation.…”

Nondestructive and Contactless Characterization Method for Spatial Mapping of the Thickness and Electrical Properties in Homo-Epitaxially Grown SiC Epilayers Using Infrared Reflectance Spectroscopy

“…Recently, it has been reported that the crystalline damage induced by ion implantation affects the infrared (IR) reflectance spectra around the reststrahlen region (~800-1000 cm -1 ) [33,34], and the difference of carrier concentration between epitaxial layer and substrate induces the interference oscillation in the near IR region (1000-4500 cm -1 ). In this study, we performed the IR reflectance measurements in the spectral range between 600 and 8000 cm -1 for high-dose phosphorus ion implanted and post-implantation-annealed 4H-SiC wafers to characterize both the electrical properties and crystalline damage of the implanted layers without destruction and contactless.…”

“…We analyzed the observed spectra to evaluate the damage of the ion implantation layers assuming that the implanted layers are composed of two phases, recrystallized SiC phase and defective SiC phase. We have derived the effective dielectric constants ε eff of implanted layers using an effective medium approximation (EMA) [33], where ε c and ε d are the dielectric constants of re-crystallized and damaged phases, respectively, and f is the volume fraction of damaged phase. We assumed that the frequency dependence of both the dielectric constants of re-crystallized phase and defective phase follows the MDF model given by eq.(1).…”