Resistive switching(RS) behaviors of Dy2 O3-based memory devices with and without Pt nanocrystals(Pt-nc) layer were investigated for nonvolatile memory applications. The Cu/Pt-nc/Dy2 O3 /Pt memory exhibits excellent unipolar RS characteristics, including highly uniform switching parameters, lower switching voltage(\1.2 V), high resistance ratio([1 9 104), a large number of switching cycles, as well as long retention time([1 9 105s), owing to the local electric field confined and strengthened near the nanocrystals' location.
Hong-Bin ZhaoHai-Ling TuFeng WeiXin-Qiang ZhangYu-Hua XiongJun Du
The band alignment of HfO_2 film on p-type(100) InP substrate grown by magnetron sputtering was investigated.The chemical states and bonding characteristics of the system were characterized by X-ray photoelectron spectroscopy(XPS).The results show that there is no existence of Hf-P or Hf-In and there are interfacial In_2O_3and InPO_4 at the interface.Ultraviolet spectrophotometer(UVS) was employed to obtain the band gap value of HfO_2.In 3d and Hf 4f core-level spectra and valence spectra were employed to obtain the valence band offset of HfO_2/InP.Experimental results show that the(5.88 ± 0.05) eV band gap of HfO_2 is aligned to the band gap of InP with a conduction band offset(ΔE_c) of(2.74 ± 0.05) eV and a valence band offset(ΔE_v) of(1.80 ± 0.05) eV.Compared with HfO_2 on Si,HfO_2 on InP exhibits a much larger conduction band offset(1.35 eV larger),which is beneficial to suppress the tunneling leakage current.
Effects of NH3 rapid thermal annealing(RTA) on the interface and electrical properties of Gd-doped HfO2(GDH)/Si stack were investigated.The process of NH3 annealing could significantly affect the crystallization,stoichiometric properties of GDH film and the interface characteristic of GDH/Si system.NH3 annealing also led to the decrease of interface layer thickness.The leakage current density of Pt/GDH/p-Si MOS capacitor without RTA was 2×10-3 A/cm2.After NH3 annealing,the leakage current density was about one order of magnitude lower(3.9×10-4A/cm2).The effective permittivity extracted from the C-V curves was～14.1 and ～13.1 for samples without and with RTA,respectively.
