HfSixOy-HfO2 Gate Insulator for Thin Film Transistors

We propose a new technique to grow HfSixOy-HfO2 lm on Si substrate by using a 500C process, and demonstrate the feasibility of multi-layered high-k oxide flm (i.e., HfSixOy-HfO2) as alternative gate insulator for thin lm transistors (TFTs). Hf metal flms were directly deposited on Si wafers at substrate temperatures of 25 400 C by using a non-reactive rf-magnetron sputtering system. Oxidation at 500 C in dry O2 ambient and subsequent annealing at the same temperature in N2 ambient result in electrically stable multi-layered HfSixOy-HfO2 gate insulator for TFTs. We also investigate the eects of the substrate temperature on the physical and electrical properties of HfSixOy-HfO2 flms, and show that substrate temperature must be set at 25 C for the sputtering of Hf metallms to obtain optimum electrical characteristics (e.g.,high dielectricconstant, no hysteresis phenomenon, and low leakage current). KCI Citation Count: 10