Preparation of AlN thin films by reactive sputtering and optical emission spectroscopy during sputtering

Abstract

Abstract Aluminum Nitride (AlN) thin films were prepared by reactive rf-magnetron sputtering in a mixed gas atmosphere composing of argon and nitrogen. The deposition rate, electrical resistivity and crystal structure were studied as a function of partial pressure of nitrogen (P N2). Total pressure(P N2+Ar) was controlled to maintain a constant pressure of 6.0 ×10−2 Pa. The structure of as-prepared films can be divided into three regions from X-ray diffraction analysis: (1) P N2 ≤ 6.0 ×10−3 Pa, Al, (2) P N2 = 1.2 ×10−2 Pa ∼ 2.4 ×10−2 Pa, a mixed phase of Al and AlN, (3) P N2 ≥ 3.0 ×10−2 Pa, AlN. With increase of P N2, the deposition rate of the films decreased drastically around P N2 = 2.4 ×10−2 Pa, and finally approached to a constant value of 25 A/min around P N2 = 6.0 ×10−1 Pa. This is proved from the measurement of optical emission spectroscopy to occur by the formation of nitride on the surface of aluminum target. AlN thin films deposited in higher P N2 exhibited a higher crystallity and a higher ref...