GROWTH-CONTROL AND PROPERTIES OF MICROCRYSTALLIZED SILICON FILMS DEPOSITED BY HYDROGEN PLASMA SPUTTERING

In this work, optical and electrical properties have been correlated t o the degree of crystallization of silicon films deposited by sputteri ng in a pure H-2 plasma at various substrate temperatures, T-s. On inc reasing T-s from 50 degrees C to 250 degrees C, the average grain size is found to grow from about 5 nm to some tens of nanometers, with a c oncomitant decrease of the optical band gap from 2.40 eV to 1.95 eV. T he detection of photoluminescence emission in the visible region for t he lowest T-s seems to originate from the quantum confinement mechanis m occurring in nanosized grains, whereas the conductivity increases by more than six orders of magnitude when T-s is increased from 50 degre es C to 250 degrees C. (C) 1997 Elsevier Science S.A.