The authors present the results of investigations carried out on the effect of magnetic field on the aging rates of island silver films deposited on glass substrates held at room temperature in a vacuum of 1 × 10-5 Torr. It is observed that the application of a magnetic field of strength 80 G during and after growth of the island film reduces the aging rate and the effect is more significant for thinner (higher resistance) films. On the basis of the mobility coalescence model it is suggested that the applied field tends to flatten the islands. © 1990 IOP Publishing Ltd.

V. Sivaramakrishnan

ISLAND SILVER FILMS

MOBILITY COALESCENCE MODEL

electric conductivity

FILMS - Metallic

Magnetic field effects

SILVER AND ALLOYS

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Influence of a magnetic field on the aging rates of island silver films

Journal of Physics D: Applied Physics

In this paper we report the results of investigations carried out on the electrical properties of silver-island films deposited onto polymethylmethacrylate-coated substrates heated to 423 K, well above the softening temperature of the polymer. For films with initial resistances less than 4.1 M/-, a sharp fall in resistance was observed which may be due to the formation of a close-packed subsurface structure. This fall in resistance occurred after a time interval of 180 s following deposition. For films with initial resistance greater than 4.1 M/-, the resistance increased enormously, marking this resistance range as a possible transition region. A film deposited at room temperature and heated behaved similarly to the silver-island films on glass substrates. © 1989 The American Physical Society.

Physical Review B

Silver-island films deposited on a substrate above its softening temperature

Results are given of experiments carried out on the stability of discontinuous silver films with overtayers of A12Os and SiO2 studied at room temperature and at 125 K. Long term stability (upto 3500 h) of two films is achieved after ageing for 700 h. The overlayers of A12O3 and SiO2 are unableto prevent oxidation and attack by water vapour of the metal islands resulting in the initial changes in resistance on exposure to atmosphere. Overlayers of A12O3 and SiO2 also do not prevent resistance increase of the films in vacuum (2 × 10−4 Pa) studied at both, room temperature and at 125 K. Resistance measurements as a function of the chamber pressure during exposure to atmosphere reveal that the films oxidise in a well defined pressure range of 6.6 Pa. Non‐linear current‐voltage (I‐U) characteristics are observed for all the films which is explained as due to a field induced structural change as indicated by an irreversible resistance change. Copyright © 1988 WILEY‐VCH Verlag GmbH &amp; Co. KGaA

physica status solidi (a)

Studies on the stability of discontinuous silver films with overlayers of Al2O3 and SiO2

The results of investigations carried out on the effect of overlayers of Al2O3, SiO2 and MoO3 on the instability of discontinuous copper films at room temperature and at 125 K, are reported. For one film, long-term stability was studied for more than 1500 h. The overlayers are inadequate in preventing movement of the islands both at room temperature and at 125 K and in providing protection against attack by atmospheric gases. The films, when exposed to the atmosphere, show a large increase in resistance in a well-defined pressure range of ≃5 × 10-2 torr, corroborating our earlier findings. The I-V characteristics at 125 K were nonlinear, the non-linearity being attributed to field-induced structural changes. © 1988 Chapman and Hall Ltd.

Journal of Materials Science

Effect of overlayers on the instability of copper island films

We report the results of the investigation carried out on the aging and field effect of discontinuous copper films deposited on glass substrates held at around 125 K. Using the scheme adopted in our earlier investigations, it was found that even at this temperature there is considerable increase in resistance. However, the agglomeration rate is much less than for films deposited at room temperature. The I-V characteristics of the films revealed an irreversible change in resistance following removal of the field. On stabilization, heating of the films revealed a decrease in resistance with temperature followed by an irreversible resistance increase beyond a transition temperature which was less than room temperature.

Fulltext

Journal of Applied Physics

Aging and field-effect studies of Cu island films at near liquid-nitrogen temperatures

Presented in this paper are the results of an investigation into the influence of a dc electric field on the growth and post-deposition resistance changes in island Ag-films deposited on glass substrates at room temperature. Based on the functional dependence of the film resistance on time, an agglomeration rate is defined with the theory of mobility coalescence invoked to explain the resistance changes in these films. It was found that the magnitude of the electric field (9 V/cm) did not influence the post-deposition coalescence but did affect the initial resistance of the film. Films studied under relative humidity conditions of greater than 85% showed an interesting crossover of the functioanl dependence of the film resistance on time consistent with earlier findings in this laboratory. Repeated deposition studies revealed that the agglomeration rate fell drastically beyond a particular deposition cycle indicating that the percolation threshold had been reached with the occurrence of large scale coalescence (LSC). © 1988.

Journal	Journal of Physics D: Applied Physics
ISSN	00223727
Open Access	No