Preparation and electrical properties of Cr_2O_3 gate insulator embedded with Fe dot

摘要

We investigated the electrical properties of a metal (Au)/insulator (magneto-electric materials: Cr_2O_3)/ magnetic materials (Fe)/tunnel layer (Cr_2O_3)/semiconductor (Si) capacitor. This capacitor shows the typical capacitance-voltage (C-V) properties of an Si-MIS capacitor with hysteresis depending on the Fe dispersibility which is determined by the deposition condition. The C-Vcurve of the only sample having a 0.5 nm Fe layer was seen to have a hysteresis window with a clockwise trace, indicating that electrons have been injected into the ultra-thin Fe layer. The samples having Fe layers of other thicknesses show a counterclockwise trace, which indicates that the film has mobile ionic charges due to the dispersed Fe. These results indicated that the charge-injection site, which works as a memory, in the Cr_2O_3 can be prepared by Fe insertion, which is deposited using well-controlled conditions. The results also revealed the possibility of an MIS capacitor containing both ferromagnetic materials and an ME insulating layer in a single system.