Electronic properties of metal/sol-gel SiO2/indium-phosphode capacitor

This work reports on the electrical properties of metal-oxide-semiconductor (MOS) capacitors made with a spin-on-glass (SOG) SiO2 layer, doped with 2% phosphorus, deposited on InP substrate by spin casting followed by a low-temperature (<260 °C) anneal. The capacitance versus voltage behavior as well as the dielectric constant of the SOG layer was analyzed as a function of the frequency. The stability of the relevant parameters was checked after a long period of time (four weeks), compared with fresh devices, and revealed a significant increase in the dielectric constant and a slight increase in the leakage current. It is shown that the use of SOG as the dielectric material in the MOS structure leads to a relatively low fixed charge (less than 2×1011 cm−2) and low fast state concentration.