Deposition and current conduction of mixed hexagonal and cubic phases of AlN/p-Si films prepared by vacuum arc discharge: Effect of deposition temperature

• AlN films containing its cubic phase were deposited by vacuum arc discharge.
• MIS capacitors of these films of (111) preferential orientation were fabricated.
• The best crystalline quality was found to be at 200 °C deposition temperature.
• The conduction mechanisms in the films were identified.
• Trapped charges at interface were estimated to be of the order of 109 cm− 2·eV− 1.

Cubic and hexagonal AlN films have been prepared by vacuum arc discharge technique at different deposition temperatures 100, 200 and 300 °C. The depositions were carried out from pure aluminum targets under nitrogen gas on p-type Si substrates, with Al forming the gate in a metal–insulator–semiconductor configuration. Preferential orientations (111) and (002) of the cubic and hexagonal phases have been affirmed by X-ray diffraction analysis. The Fourier transform infrared spectra revealed the manifestation of the two phases as well. The effect of deposition temperature on the crystalline quality and texture of the films has been also investigated and the grain size of which, has been evaluated as a function of temperature. The best crystalline quality i.e., largest grain size was found to be at 200 °C. The composition and stoichiometry of the films have been determined by the time-of-flight elastic recoil detection analysis (TOF-ERDA) and Rutherford backscattering techniques. The Al/N ratio was found to be around 1, while the O content was less than 1.8%. Scanning electron microscopy and TOF-ERDA measurements demonstrated films thickness of 260 nm. Current density versus electric field and capacitance–voltage (C–V) measurements were also investigated to reveal the field emission and conduction mechanism of the Al/AlN/p-Si devices. Schottky, Pool–Frenkel and Fowler–Nordheim conduction have been found to contribute to the electron transport, and the best emission properties were manifested at 200 °C with a highest current density 525 μA/cm2 at a field 71 V/μm. From C–V curves, the density of traps has been estimated to be 18 × 109 cm− 2 eV− 1 indicating a good quality of the deposited films.