For a nanoCMOS of sub-65nm technology, where the gate oxide (SiO2) thickness is very low, the gate leakage is one of the major components of power dissipation. In this paper, we provide analytical models to describe the tunneling current and propagation delay of behavioral level components considering various physical effects in the absence of foundry data. Subsequently, we explore the use of multiple oxide thickness resources as a technique for the reduction of gate leakage. In particular, we introduce a behavioral datapath scheduler that maximizes the utilization of higher gate oxide thickness resources. We characterize behavioral components for both 65nm and 45nm technologies in order to study the trend of tunneling current as technology scales, and provide them as inputs to the scheduler. We carried out extensive experiments for several benchmarks and observed significant reduction in gate leakage.