The capacitance-voltage characteristics and hydrogen concentration in phospho-silicate glass films: Relation to phosphorus concentration and annealing effects

Abstract

Capacitance-voltage (C-V) characteristics of the low-pressure chemical vapor deposited phospho-silicate glass (P-glass) films deposited on thin (∼250 Å) thermal SiO2 films on silicon have been investigated as a function of the phosphorus content and rapid thermal annealing in the temperature range of room temperature to 450 °C carried out in various ambients. Simultaneously, the quantitative hydrogen concentration depth profiles of both as-deposited and annealed oxide films were obtained using the nuclear reaction technique. The C-V characteristics were found to be related to the charges in the oxide. The charge density, in turn, is controlled by both the phosphorus and the hydrogen (hydrogenous species) concentration in the films. An interactive relationship that controls the C-V characteristics is postulated between the presence of phosphorus and hydrogen and their concentrations in these oxides. A schematic model is presented that also postulates that hydrogenous species of two different characters are present in these films: one that easily comes out of the film at low temperature annealing and the other that comes out at significantly higher temperatures.