Aluminum nitride thin film deposition using DC sputtering

Abstract

Aluminum nitride thin film depositions at a low temperature become one of the most promising fields in micro-electro mechanical systems and in the semiconductor industry; because of its good compatibility with designs on silicon substrates, its mechanically strong, chemically stable, wide bandgap energy (≈6.2 eV), and has a large electro-mechanical coupling constant. An AlN thin film deposition using DC Magnetron sputtering have the advantage over other deposition methods due to its simplicity, better parameter control, cheapness, and requires a low deposition temperature. The NTI nano film DC sputtering system was used to deposit the AlN thin film with 99.99% pure aluminum target material and 100 silicon substrates, the working temperature is at 20C°, there is a 10Cm separation distance between the target and the substrate, 335~351 V cathode voltage, the foreline and base pressures are 2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> T, 4×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> T respectively, and uses 200W DC power. We vary the time and nitrogen/argon gas flow ratio. Deposited film was characterized by X-ray diffraction and (002) of wurtzite hexagonal phase of AlN thin film was found with beak intensity of 800 count per second for 50% nitrogen content. Field Emission Scanning Electron Microscopy was used to study thin film cross section, film thicknesses and deposition flow rate at different times and gas flow ratio, there is inverse relationship between nitrogen gas percentage deposition and flow rate. Deposition flow rate are 4.12 nm/ min for 50% nitrogen and 2.217 nm/min for 75% of nitrogen content.