Low-operation voltage conductive-bridge random access memory based on amorphous NbS.

Amorphous NbS was proposed as the resistive switching (RS) layer for conductive-bridge random access memory (CBRAM) for the first time, with Cu and Au as the top and bottom electrodes, respectively. NbS films were prepared at room temperature, which exhibited an amorphous structure and did not crystalize even annealed at 500°C, showing good thermal stability. The amorphous NbS CBRAM devices present stable bipolar non-volatile RS characteristics. Repetitive RS behavior is demonstrated in amorphous NbS CBRAMs. The operating voltage during all RS cycles is less than 1 V, demonstrating that the NbS CBRAM is a low-operation voltage memory device. The distribution of the high and low resistive state resistance is relatively concentrated, and the on-off ratio has been kept above 100, offering a sufficient data read/write window. The formation and fracture of the Cu metal conductive filament is considered to be the RS mechanism by analyzing the dependence of current and voltage in logarithmic coordinates. Our study demonstrated that amorphous NbS is a promising material for low-operation voltage CBRAM.