Properties Of AlN Thin Films Research Articles

On the properties of AlN thin films grown by low temperature reactive r.f. sputtering

In this paper we report on the growth of c-axis-oriented AlN thin films by low temperature reactive r.f. sputtering and the results of their examination and analysis in a variety of ways. In addition to using other substrates, we fabricated c-axis- oriented AlN films on aluminium film substrates. A hexagonal column structure was observed in the morphology of replicas of the natural surfaces of films. As well as the dielectric constant ε, the resistivity ϱ, the breakdown field E p and the refractive index n, curves of ε versus frequency f, ε versus temperature T and conductivity σ versus T were measured. The IR absorption spectrum of an AlN film sputtered at low temperature coincides with that of an AlN film sputtered onto a high temperature substrate and of a bulk crystal, which remains unchanged after annealing. The band gap E g = 5.9–6.0 eV, which remains unchanged after annealing in N 2 at 900°C. Theoretical calculation of the dispersion curve of surface acoustic waves by an AlN/glass structure shows that the curve is very level in the range hk = 0.2–0.6. The capacitance-voltage curve of an Al/AlN/Si structure is given in this paper.