Jerome Michael Eldridge

Reactive ion etching induced corrosion of Al and Al‐Cu films

Aluminum and Al‐Cu conductor lines etched with a Cl containing plasma in low‐pressure diode systems corroded rapidly upon atmospheric exposure. The mechanisms underlying this corrosion problem were investigated using Auger electron and x‐ray photoelectron spectroscopies. Reactive ion etching resulted in a nonprotective oxide layer and thus rendered the etched samples more susceptible to atmospheric corrosion. Factors contributing to the increased reactivity of etched samples includes C and Cl contamination, radiation damage, and for Al‐Cu alloys, Cu enrichment. A thermal oxidation treatment at temperatures of ∼300–350 °C and l atm O2 pressure for ≳30–45 min was found to be effective in restoring the protective oxide layer and thus improving the corrosion resistance of etched samples.

Oxidation of Plasma‐Deposited α ‐ Si x C 1 − x : H Films

The thermal oxidation characteristics of α-Si x C 1-x :H films were studied for compositions from x=0.25 to 0.51 and varying hydrogen concentrations. The carbide films were plasma-deposited onto oxidized Si substrates, using two differently configured deposition systems; silane, methane, and argon gas mixtures; and, temperatures from 200° to 600°C. The films were oxidized in either dry oxygen or air (with approx. 1 volume percent water) for times between 1 and 270h and temperatures from 500° to 900°C. The resulting oxide surface layers were characterized by etch rate, profilometry, XPS, and RBS techniques and were determined to consist of virtually stoichiometric SiO 2 at the outermost surface with perhaps small islands of unreacted carbide remaining near the inner interface. The kinetic analysis suggested that the large observed increases in the linear and parabolic rate constants with decreasing x could be attributed to preferential attack on C-H bonds which are more prevalent in the graphitic, C-rich films than in the tetrahedrally coordinated, Si-rich ones

Alloy compositional profiles by AES, ESCA, and ion sputtering: Air‐exposed Fe1−xPdx films

Surface studies of air‐exposed, 1000 A‐thick Fe1−xPdx alloy films with x=0.06–0.74 were carried out using AES, ESCA, and in situ ion sputtering techniques. It was found that Fe is preferentially oxidized on the surface with a Pd‐enriched region formed underneath the oxide layer. The iron oxide thickness decreases linearly as the Pd concentration is increased, becoming quite small for x≳0.6. Fe2O3 is the dominant oxidation product for the lower Pd concentration alloys while Fe3O4 appears to be the major oxide for x≳0.36. The steady state composition of the surfaces measured both by AES and ESCA techniques afer prolonged sputtering also indicated that the relative Pd‐to‐Fe sputtering yield remains constant for films with x between 0.06 and ∠0.38 and decreases to another constant value for films with larger x values. No preferential sputtering is observed in the AES case for alloys with x≳0.38, if the atomic density is taken into account; for x<0.38, Pd sputters about twice as fast as Fe. In the ESCA case, v...

A Comparison of the Mass and Resistance Change Techniques for Investigating Thin Film Corrosion Kinetics

Quartz crystal oscillator microbalance (QCM) and electrical resistance change (RC) measurements were carried out simultaneously in situ on identically prepared Permalloy films in order to establish the sensitivity and reproducibility of each technique for investigating atmospheric corrosion. Both techniques were found to be highly sensitive to thickness changes (better than 1A) resulting from corrosion in a high-humidity atmosphere containing trace quantities of acid-forming, gaseous pollutants. However, the QCM results were found to be noticeably more reliable than the RC data. Moreover, it was established from the QCM findings that the average mass increase due to corrosion was quite closely proportional to the square root of exposure time in the test chamber. Thus, complex thin-film corrosion kinetics can be determined with considerable accuracy provided reasonable experimental procedures are employed. The results of both measurements were compared also in an isochronal plot, where it was found that the resistance change was proportional to the square of the mass increase arising from the formation of corrosion products. The origin of this relationship was investigated by carrying out simulated corrosion studies involving punching out holes in an aluminized Mylar structure while determining the effects of material loss on electrical resistance. 7 figures.

Effects of applied stress on UHV‐deposited Fe1−xPdx thin films

The effect of an externally applied stress on the B‐H loops of UHV‐deposited Fe1−xPdx thin films depend strongly on composition. A uniaxial compressive stress increasingly applied along the easy axis of fcc films (x≳0.31) causes the usual distortion of the easy‐axis loop toward the appearance of hard‐axis loop. Similar stresses applied to bcc films (x≲0.31), however, produce no significant changes in the easy‐axis loop until x approaches 0.31 despite the fact that the magnetostriction coefficient only ranges over a factor of 2 for x⩾0.12 (λ⩾15×10−6). This locking of the easy axis in bcc films also affects the strain sensitivity which is 0 in the limit of 0 strain, although it approaches the expected value with increasing strain. Several possible origins for this behavior are discussed.