303 nm thick aluminum nitride (AlN) film deposited by reactive sputtering.
1) L. Yu. Beliaev, E. Shkondin, A. V. Lavrinenko, O. Takayama. Thickness-dependent optical properties of aluminum nitride films for mid-infrared wavelengths, J. Vac. Sci. Technol. A39, 043408 (2021) 2) L. Yu. Beliaev, E. Shkondin, A. V. Lavrinenko, O. Takayama. Erratum: Thickness-dependent optical properties of aluminum nitride films for mid-infrared wavelengths [J. Vac. Sci. Technol. A 39, 043408 (2021)], J. Vac. Sci. Technol. A40, 027001 (2022) (Numerical data kindly provided by Osamu Takayama)
AlN, or aluminum nitride, is a wide-bandgap semiconductor material that crystallizes in a wurtzite or hexagonal structure. With a bandgap of approximately 6.1 eV, AlN has excellent thermal and electrical insulation properties. One of the most significant attributes of AlN is its high thermal conductivity, which makes it an ideal material for electronic packaging and thermal management applications. In the optical domain, AlN is transparent in the ultraviolet and visible range, and its high refractive index makes it a candidate for optoelectronic devices like light-emitting diodes (LEDs) and laser diodes, especially those operating in the ultraviolet spectrum. It also serves as a substrate for the growth of other wide-bandgap materials, facilitating the development of high-power and high-frequency electronic devices. AlN is often used in heterostructures, combining with other III-V or II-VI materials to achieve specific electronic or optical functionalities. Despite its advantages, the material poses challenges in terms of high-quality crystal growth and doping efficiency, which are active areas of ongoing research. Overall, AlN remains a critical material in the semiconductor industry, offering a unique combination of thermal, electrical, and optical properties that are leveraged in a wide array of applications.