Polarization Phenomena and Other Properties of Phosphosilicate Glass Films on Silicon

Abstract

A study has been made of phosphosilicate glass films prepared by pre‐depositing on thermally oxidized silicon. Many of the properties of these films including composition, density, etch rate, conductivity, dielectric constant, and dielectric strength have been measured and are compared with the corresponding properties of thermally produced silicon dioxide layers. A polarization effect is discussed which gives rise to an increase of about 20% in the dielectric constant of the glass at high temperatures and low frequencies (∼ 250°C at 50 cps). Under d‐c bias at lower temperatures this polarization causes a slow drift in the capacitance‐voltage characteristic of metal‐oxide‐semiconductor (MOS) capacitors which use the glass as a dielectric. The MOS capacitance‐voltage method is used to study the time, temperature, and voltage dependence of the polarization, and mechanisms are discussed which can account for the observed results.