Fabrication and electrical properties of metal-oxide semiconductor capacitors based on polycrystalline p-CuxO and HfO2/SiO2 high-κ stack gate dielectrics

Polycrystalline p-type CuxO films were deposited after the growth of HfO2 dielectric on Si substrate by pulsed laser deposition, and CuxO metal-oxide-semiconductor (MOS) capacitors with HfO2/SiO2 stack gate dielectric were primarily fabricated and investigated. X-ray diffraction and X-ray photoelectron spectroscopy were applied to analyze crystalline structure and Cu+/Cu2+ ratios of CuxO films respectively. SiO2 interlayer formed between the high-κ dielectric and substrate was estimated by the transmission electron microscope. Results of electrical characteristic measurement indicate that the permittivity of HfO2 is about 22, and the gate leakage current density of MOS capacitor with 11.3 nm HfO2/SiO2 stack dielectrics is ∼ 10−4 A/cm2. Results also show that the annealing in N2 can improve the quality of CuxO/HfO2 interface and thus reduce the gate leakage density.