Characteristics of hafnium oxide grown on silicon by atomic-layer deposition using tetrakis(ethylmethylamino)hafnium and water vapor as precursors

The growth of HfO2 thin films on a HF-dipped p-Si(100) substrate at 200 degrees C by atomic-layer deposition (ALD) using Hf[N(C2H5)(CH3)](4) and H2O vapor as precursors is demonstrated. Uniform HfO2 thin films are obtained on a 4-in. silicon wafer, and the energy-band gap and band offset are determined by x-ray photoelectron spectroscopy analysis. The as-deposited HfO2 thin film is amorphous and able to crystallize at 500 similar to 600 degrees C with only the monoclinic phase. As for the electrical performance of Au-Ti-HfO2-Si metal oxide semiconductor capacitors, a dielectric constant of similar to 17.8 and an equivalent oxide thickness value of similar to 1.39 nm are obtained from the 40-cycle ALD film after annealing at 500 degrees C. In addition, the breakdown field is in the range of 5 similar to 5.5 MV/cm, and the fixed charge density is on the order of 10(12) cm(-2), depending on the annealing temperatures. The interface quality of HfO2 thin films on silicon is satisfactory with an interface-trap charge density of similar to 3.7 x 10(11) cm(-2) eV(-1).