Development of Low Temperature Oxidation Process Using Ozone for VLSI

Abstract: With decreasing size of MOS transistor the thickness of gate oxide (SiO2) is reaching in regime where it is just 2-3 atomic layers thick about 1 to 1.5 nm thick because of thin oxide layers there is direct tunnelling of charge carriers through gate oxide, and the transport of charge carriers through defects in gate oxide. The increasing leakage current through gate oxide is proving to be a showstopper to the scaling of MOS transistor, and saturating the Moore’s Law. For the applications, where the devices are need to be fabricated on plastic, glass or poly-crystalline silicon substrates a good quality of oxide is required to be grown at low temperatures. In this work a low temperature, defect free oxide growth technique using ozone is presented and we study the effect of various ambient temperatures on growth of SiO2, the effect of pre cleaning and passivation on quality of ozone grown oxide in terms of bulk defect density, Si-SiO2 interface trap charge density and on oxide life time is presented.

Keywords: MOS (Metal Oxide Semiconductor), FET (Field Effect Transistor), TDDB (Time Dependent Dielectric Breakdown), Dit (Density of Interface Traps).