Optical properties of AlN determined by vacuum ultraviolet spectroscopy and spectroscopic ellipsometry data

Abstract

Precise and accurate knowledge of the optical properties of aluminum nitride (AlN) in the ultraviolet (UV) and visible (VIS) regions is important because of the increasing application of AlN in optical and electro-optical devices, including compact disks, phase shift lithography masks, and AlN/GaN multilayer devices. The interband optical properties in the vacuum ultraviolet (VUV) region of 6-44 eV have been investigated previously because they convey detailed information on the electronic structure and interatomic bonding of the material. In this work, we have combined spectroscopic ellipsometry with UV/VIS and VUV spectroscopy to directly determine the optical constants of AlN in this range, thereby reducing the uncertainty in the preparation of the low-energy data extrapolation essential for Kramers-Kronig analysis of VUV reflectance. We report the complex optical properties of AlN, over the range of 1.5-42 eV, showing improved agreement with theory when contrasted with earlier results.

Optical Properties and van der Waals - London Dispersion Interactions of Polystyrene Determined by Vacuum Ultraviolet Spectroscopy and Spectroscopic Ellipsometry

“…To quantitatively determine the electronic structure of PS we have used Kramers-Kronig analysis [50,51] to determine the complex optical properties of PS over the complete energy range, encompassing the valence electronic structure. These results are essential information to calculate the full spectral Hamaker constants for vdW-Ld dispersion interactions for configurations including PS.…”

Dielectric Function of AlN Grown on Si (111) by MBE

“…Our work is similar to that of Jones et al [5], except that their films were prepared by RF sputtering. Our AlN films were grown using MBE on low-resistivity Si (111), cut 3° off towards (110), at 860°C with ammonia as the nitrogen source, therefore they might contain some hydrogen or silicon, which tend to reduce n. Because of the high affinity of AlN for oxygen, contamination with oxygen is a possibility [4], which would also reduce the value of n. Infrared transmission measurements of AlN on high-resistivity two-side polished Si are planned to determine the impurity content.…”

“…Much of the early results are based on pioneering work by Slack, who synthesized high-purity AlN single-crystals and studied their properties, particularly the high thermal conductivity [2,3]. Recent interest in AlN has shifted to thin films prepared on different substrates (Si, SiC, sapphire) using a variety of techniques, such as molecular beam epitaxy (MBE), chemical vapor deposition [4], and RF sputtering [5].…”

Recent developments of wide-bandgap semiconductor based UV sensors

“…For the purpose of VUV radiation detection, the penetration depth 1/α(λ) of diamond and AlN materials derived from [11][12][13][14][15][16][17] drops drastically to extremely small values of the order of few nanometres. As shown in Fig.…”