High-k Film And Silicon Contact Electrical Properties

In this work,the electrical characteristics of Al/Al₂O₃/Si and Al/HfAlO/Si type Metal-Oxide-Semiconductor(MOS) capacitor were studied.By Deep Level Transient Spectroscopy(DLTS),Capacitance-Voltage(CV) and theoretical simulation,the interface characteristics and anneal effect of samples were investigated systematically. The major results are given as follows:1.In the CV testing of Al₂O₃ and HfAlO samples with different composition rates,certain positive charges were introduced into oxide by anneal in N₂ and N₂/H₂, and the slow interface states were found to decrease significantly after anneal.2.In the DLTS measurement of MOS capacitor,the active energy doesn't invariably correspond to the energy level of traps but the distance between conductance band and Fermi level,which is also obtained by theoretical calculation. The active energy of capture cross section of Al₂O₃ is found to be 0.25eV by Insufficient-Filling DLTS and used to modify the model.At the same time,in the Al₂O₃ samples' DLTS measurement,the trend of the active energy of capture cross section with static voltage also proves the major traps exit on the interface between Al₂O₃ between Si.3.In the HfAlO samples' DLTS measurement,the active energy doesn't vary with static voltage.After analysis,the origin of such traps should be traps in the oxide very close to the interface.With the Insufficient-Filling DLTS,the active energy of capture cross section is found to be 0.08eV.Therefore,the true energy of traps is 0.36ev above the valance band of Si.In the DLTS measurement of samples with different composition rates and different anneal conditions,the active energy was found to decrease with increases in anneal temperature and composition rate of HfO₂. The variation of traps' density is showed by the variation of the peak's height.