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. It is about 1 to 1.5 nm thick and due to thin oxide layers there is direct tunneling 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. 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 as been studied. In this thesis, we are designing a 8-Bit ring oscillator using FinFETs in which ring oscillators has been designed using ozone oxidized FinFETs and without ozone oxidized FinFETs.While comparing the results we found that the ring oscillator using ozone oxidized FinFETs shows significantly better results as compared to ring oscillator without ozone oxidized FinFETs and thus the application of ozone in VLSI has been described and justified. The design layout is prepared on the tool LASI and the application of ozone on the design is done through CADENCE tool and finally the simulation and results on MATLAB 7.0 is carried out. The technology used is 60 nm.