Simplified ZrTiO x -based RRAM cell structure with rectifying characteristics by integrating Ni/n + -Si diode

Area of Science:

• Materials Science
• Electrical Engineering
• Solid-State Physics

Background:

• Resistive switching random access memory (RRAM) faces challenges with sneak currents in high-density crossbar arrays.
• Integrating diodes within RRAM cells is crucial for suppressing these sneak paths and improving array efficiency.
• Existing diode-integrated RRAM solutions often involve complex structures or additional fabrication steps.

Purpose of the Study:

• To propose and characterize a simplified one-diode, one-resistor (1D1R) RRAM cell structure.
• To demonstrate the effectiveness of a metal/semiconductor Schottky diode for current rectification in RRAM.
• To evaluate the performance and reliability of the proposed 1D1R RRAM cell.

Main Methods:

• Fabrication of a four-layer TaN/ZrTiO x /Ni/n(+)-Si structure for the 1D1R RRAM cell.
• Electrical characterization of the cell's resistive switching behavior, including SET/RESET voltages and endurance.
• Analysis of current rectification properties using forward/reverse current ratios.
• Assessment of data retention characteristics.

Main Results:

• The 1D1R cell exhibits bipolar resistive switching with low SET/RESET voltages (~1 V) and no forming process required.
• Significant current rectification was achieved, with a forward/reverse current ratio exceeding 10^3.
• A high resistance ratio (>10^3) between high and low resistance states was observed.
• The cell demonstrated robust reliability, including data retention up to 10^4 s and endurance of 10^5 cycles.

Conclusions:

• The proposed four-layer 1D1R RRAM cell effectively suppresses sneak current using an integrated Schottky diode.
• The device shows excellent switching characteristics, rectification efficiency, and reliability.
• This simplified structure holds significant potential for next-generation nonvolatile memory technologies.