STUDY OF HIGH-K DIELECTRICS FOR MIS CAPACITOR APPLICATIONS

Abstract

Scaling of integrated circuits (IC) into nanoscale technology node requires a gate dielectric material of thickness near to 20A°. This ultrathin feature shows evidences of a large direct tunnelling current into gate. To reduce this tunnelling effect high-k dielectrics which have large dielectric constant compared to Si02 are investigated in many literatures. However a manufacurable solution of high-k material for nanoscale technology is not available. In this dissertation, to investigate the properties of gate dielectric materials MIS capacitors, Al/Hf02/p-Si, A1/ZrO2/p-Si and laminated structures of Al/ZrO2/HfO2/p-Si and Al/Hf02/ZRO2/p-Si, are fabricated using RF Magnetron sputtering. Electrical and physical characterization is studied with variation in annealing temperature and reliability nature. The reliability characteristics are made in case of binary and laminated MIS capacitors. Results shows high-k materials (Zr02, Hf02) with dielectric constant 15-22 are reported. Study of annealing shows Hf02 coated films tend to poly crystalline nature from amorphous at 450°C annealing with N2. From the electrical characterization decrease in positive oxide charge present inside the dielectric material is reported. Reliability analysis shows degradation of dielectric performance is mainly due to induced oxide charges inside the dielectric. This effect is observed in both binary and bilayer structures of Zr02 and Hf02