RELAXATIONAL POLARIZATION AND CHARGE INJECTION IN THIN-FILMS OF SILICON-NITRIDE

Relaxational polarization phenomena and charge injection in silicon ni tride deposited on an n-type silicon substrate are studied. After appl ication of low electric fields (<1 MV cm(-1)), currents with a time de pendence j similar to t(-alpha), alpha approximate to 1 in a time rang e 500 ns less than or equal to-t less than or equal to 10,000 s flow t o the dielectric. After shore circuiting, currents with the same time behaviour but opposite sign flow back in the outer circuit. These curr ents are due to reversible proton fluctuations within the silicon nitr ide. At higher field strengths, a charge injection process sets in. Ab out 0.05 s after application of a field E=3.5 MV cm(-1), the currents deviate from the t(-1) law and become constant. This charge injection process depends upon the density of protons within the silicon nitride .