Electrical Characterization of Defects Created by γ-Radiation in HfO2-Based MIS Structures for RRAM Applications

The γ-radiation effects on the electrical characteristics of metal–insulator-semiconductor capacitors based on HfO2, and on the resistive switching characteristics of the structures have been studied. The HfO2 was grown directly on silicon substrates by atomic layer deposition. Some of the capacitors were submitted to a γ ray irradiation using three different doses (16 kGy, 96 kGy and 386 kGy). We studied the electrical characteristics in the pristine state of the capacitors. The radiation increased the interfacial state densities at the insulator/semiconductor interface, and the slow traps inside the insulator near the interface. However, the leakage current is not increased by the irradiation, and the conduction mechanism is Poole–Frenkel for all the samples. The switching characteristics were also studied, and no significant differences were obtained in the performance of the devices after having been irradiated, indicating that the fabricated capacitors present good radiation hardness for its use as a RS element.This work have been supported by the Spanish MINECO with FEDER funds under grants TEC2014- 52512-C3-3-R, TEC2014-52512-C3-1-R and TEC2014-54906-JIN