Interfacial and Breakdown Characteristics of MOS Devices with Rapidly Grown Ultrathin SiO2 Gate Insulators,

Metal-oxide-semiconductor devices fabricated with tungstenn polysilicon composite gates and subhundred-angstrom SiO2 gate insulators grown by rapid thermal oxidation were characterized by various electrical measurements. The as-fabricated devices with unannealed rapidly grown oxides exhibited breakdown characteristics superior to furnace-grown oxides as evidenced by their excellent breakdown uniformity, an average breakdown field of 15 MVcm, and an average breakdown charge density of over 50 C sq cm 2 at a stress current density of 1 Asq cm. The preoxidation surface cleaning procedure was observed to affect the charge-to-breakdown and the densities of fixed oxide charges and surface states in these MOS structures.