Metal oxide semiconductor field effect transistor characteristics with iridium gate electrode on atomic layer deposited ZrO2 high-k dielectrics

Abstract

We have investigated metal oxide semiconductor (MOS) characteristics with Ir gate on ZrO2 dielectrics gate structure. The ZrO2 films are grown with atomic layer deposition-method using O-2 and tetrakis (diethyl amino) zircumium (TDEAZ) as a Zr precursor. Some ZrO2 films are also grown with oxygen plasma along with TDEAZ. The ZrO2 grown with oxygen plasma shows the EOT value of 1.39 nm, high k of 18.2 and little hysteresis of 20 mV, whereas EOT and k values of the ZrO2 films grown with O-2 are 1.52 nm, 13.34 nm, respectively. This is due to dense and well-matched stoichiometric ZrO2 and interfacial reaction through the diffusion of oxygen in the oxygen plasma. Metal oxide semiconductor. field effect transistor. (MOSFET),, characteristics of Ir/ZrO2 grown with oxygen plasma/Si gate structured transistor reveals that the effective mobility is 226 cm(2)/Vs at V-GS = 1.5 V, which is slightly smaller than the saturation mobility of 250 cm(2)/Vs. The interface trap density in the ZrO2 grown with oxygen plasma is also lower than that in the ZrO2 grown with O-2.