Study of Lanthanum incorporated HfO2 nano-scale high-κ dielectric using Dense Plasma Focus for metal–insulator–metal capacitor applications

Metal–insulator–metal (MIM) capacitors have been fabricated using high-κ La2O3\HfO2 dielectric stacks deposited using Dense Plasma Focus (DPF) and were subsequently studied. DPF is a unique machine used for the very first time to fabricate dielectric stacks within a MIM structure as it can be used both to deposit nano-size thin film as well as can also be used to change the properties of the postdeposited thin film. The films were first deposited under preoptimized conditions of DPF device to have best focus for producing ions. The substrate for deposition of dielectric stacks of La2O3\HfO2 was placed at an optimized distance from the focus under argon ambient. The electrical characterization of the dielectric stacks were investigated employing WLa2O3\HfO2–Al-Si MIM capacitor structure deposited using DPF. The microstructure of dielectric film is examined by using AFM and the thickness of the film is examined using an ellipsometer. The crystallinity of the various post-deposited dielectric films was characterized by High Resolution X-ray diffraction. Fabricated MIM capacitors are characterized for the determination of capacitance density, dielectric constant and leakage current density for different levels of lanthanum incorporation. It can be seen that Lanthanum incorporation in HfO2 based dielectric stacks has high band gap, good thermal stability and low leakage current which makes it one of the most promising candidates for metal–insulator–metal capacitor