Impact of Density of States on the Characteristics of Channel-All-Around InGaZnO Field-Effect Transistors

The vertical channel-all-around (CAA) field-effect transistor (FET) based on indium-gallium-zinc-oxide (IGZO) shows great promise for applications in novel dynamic random access memory architectures. In this work, the impact of density of states (DOS) on the performance of IGZO CAA FETs is studied by way of experiments and technology computer-aided design simulations. A model of the device has been developed that examines the impact of the critical DOS parameters. It is found that device parameters, including threshold voltage, subthreshold swing (SS), and field-effect mobility, are directly impacted by electron acceptor-like Gaussian-distributed states and conduction band tail states. The study presented here provides insight into how the DOS in the IGZO quantitatively impacts the device performance, for subsequent design technology co-optimization of CAA transistors.