The memory characteristics of a flash memory device using c-axis aligned crystal indium gallium zinc oxide (CAAC-IGZO) thin film as a channel material were demonstrated. The CAAC-IGZO thin films can replace the current poly-silicon channel, which has reduced mobility because of grain-induced degradation. The CAAC-IGZO thin films were achieved using a tantalum catalyst layer with annealing. A thin film transistor (TFT) with SiO2/Si3N4/Al2O3 and CAAC-IGZO thin films, where Al2O3 was used for the tunneling layer, was evaluated for a flash memory application and compared with a device using an amorphous IGZO (a-IGZO) channel. A source and drain using indium-tin oxide and aluminum were also evaluated for TFT flash memory devices with crystallized and amorphous channel materials. Compared with the a-IGZO device, higher on-current (Ion), improved field effect carrier mobility (μFE), a lower body trap (Nss), a wider memory window (ΔVth), and better retention and endurance characteristics were attained using the CAAC-IGZO device.

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Coordinated multi-point (CoMP) -joint processing (JP) is a technique which improves the cell edge user data rate and spectral efficiency. The practical requirements for CoMP-JP in terms of capacity and latency constraints should be solved by considering backhaul network. The possibility of deploying CoMP-JP in practical cellular systems strongly depends on the backhaul network capabilities. The authors propose a selective clustering scheme which is able to selectively form clusters in order to decrease the traffic load of the backhaul network for CoMP-JP. In addition, the authors propose a new frequency reuse scheme for downlink CoMP-JP. The authors are able to decrease intra-cell and inter-cell interference with our proposed frequency reuse scheme. Therefore the authors increase the spectral efficiency and SINR (signal to interference and noise ratio) performance of the system.