The bipolar resistive switching characteristics of resistive random access memory (ReRAM) based on HfO2 thin films have been demonstrated by using Ag/HfO2/Pt structured ReRAM device. MIcrowave irradiation (MWI) treatment at low temperature was employed in device fabrication with HfO2thin films as a transition layer. Compared to the as-deposited Ag/HfO2/Pt device, highly improved uniformity characteristics of resistance values and operating voltages were obtained from the MWI treatment Ag/HfO2/Pt ReRAM device. In addition, a stable DC endurance (> 100 cycles) and a high data retention (> 104 sec) were achieved.

In this paper, reliability of the two sandwiched MIM capacitors of Al2O3-HfO2-Al2O3 (AHA) and SiO2-HfO2-SiO2 (SHS) with hafnium-based dielectrics was analyzed using two kinds of voltage stress; DC and AC voltage stresses. Two MIM capacitors have high capacitance density (8.1 fF/μm2 and 5.2 fF/μm2) over the entire frequency range and low leakage current density of ∼1 nA/cm2 at room temperature and 1 V. The charge trapping in the dielectric shows that the relative variation of capacitance (ΔC/C0) increases and the variation of voltage linearity (α/α0) gradually decreases with stress-time under two types of voltage stress. It is also shown that DC voltage stress induced greater variation of capacitance density and voltage linearity than AC voltage stress.

Hafnium oxide (HfO2) was very advantageous for substitute material of gate on existing transistor. HfO2 has been widely studied due to high contact with polysilicon and thermal stability and also, it is easily etched by using HF solution. In this study, HfO2 and thermal oxide films were etched by wet etch method using chemical etchant. Etch rate of HfO2 and thermal oxide was linearly increased with increasing concentration of HF and temperature but etch rate of HfO2 was higher than thermal oxide due to H+, F-, and HF2- ions at below 0.5% concentration of HF. And also, etch selectivity was improved by adding Hydrazine as additive.

In this study, we fabricate resistive switching random access memory (ReRAM) devices constructed with a Al/HfO2/ITO structure on glass substrates and investigate their memory characteristics. The hafnium oxide thin film used as a resistive switching layer is sputtered at room temperature in a sputtering system with a cooling unit. The Al/HfO2/ITO device exhibits bipolar resistive switching characteristics, and the ratio of the high resistance (HRS) to low resistance states (LRS) is more than 60. In addition, the resistance ratio maintains even after 10(4) seconds.