RF Sputtered Aluminum Oxide Films on Silicon

Abstract

The physical and electrical properties of aluminum oxide films deposited on silicon by rf sputtering from an alumina target in an argon atmosphere were investigated as a function of sputtering power density in the range from 0.5 to 3 W/cm2. The deposition rates ranged from 20 to 80 Aå/min. The density, index of refraction, and dielectric constant of the films increased while the etch rate decreased with increasing power density. The surface charge at the aluminum oxide‐silicon interface was typically larger than 1012 e/cm2. This charge increased with increasing sputtering power density and could be reduced to 7–8×1011 normale/cm2 by annealing. The films exhibited trapping instabilities at room temperature but no polarization was observed under bias‐temperature stress. The characteristics of composite layers of thermally grown silicon dioxide and sputtered aluminum oxide layers on silicon were also investigated and found to exhibit low surface charge densities, no hysteresis, and a “contact potential” as well as charge stored at the interface between the two insulators.

Some Properties and Electrical Instabilities in RF Sputtered Niobium Oxide Films

“…The film thickness for the respective sample is tabulated in Table I. Low film density related to low power density has been reported (13,14). Similar observations of the deterioration of the silicon surface properties in using high power densities were also reported by Hu and Gregor (13) and Salama ~14).…”

Charge in SiO[sub 2]-Al[sub 2]O[sub 3] Double Layers on Silicon

“…Gosney (8) finds a negative single layer of charge (7 • 10 n charges/cm2), no contact potential and no bulk charge; he reports also that the effective charge is positive when A1203 is deposited directly on silicon. Salama (4) reports a single layer of positive charge at the interface and a contact potential of about +IV in his double layer structures; both positive and negative charge can be observed in the Al~O3-Si structure depending on the sputtering conditions and the annealing conditions (4,5).…”

Properties of radio frequency–sputtered alumina films on flat and grooved substrates

“…Alumina films have been made by a wide range of techniques, including anodization, plasma anodization, chemical vapor deposition, solgel methods, molecular beam epitaxy, reactive evaporation, dc magnetron 1-4 reactive sputtering, and rf [5][6][7][8][9][10][11] and rf magnetron 12,13 sputtering in an inert or reactive gas plasma. Alumina films have been made by a wide range of techniques, including anodization, plasma anodization, chemical vapor deposition, solgel methods, molecular beam epitaxy, reactive evaporation, dc magnetron 1-4 reactive sputtering, and rf [5][6][7][8][9][10][11] and rf magnetron 12,13 sputtering in an inert or reactive gas plasma.…”