Conduction Mechanisms in Resistance Switching Memory Devices Using Transparent Boron Doped Zinc Oxide Films

Area of Science:

• Materials Science
• Solid-State Physics
• Device Engineering

Background:

• Transparent conductive oxides (TCOs) are crucial for electronic devices.
• Zinc oxide (ZnO) based materials offer tunable electronic properties.
• Resistance switching memory (RRAM) is a promising next-generation memory technology.

Purpose of the Study:

• To fabricate and investigate metal/oxide/metal capacitors using transparent boron-doped zinc oxide (ZnO:B) films.
• To evaluate the suitability of ZnO:B films for resistance switching memory applications.
• To understand the conduction mechanisms and material properties of ZnO:B films in memory devices.

Main Methods:

• Fabrication of metal/oxide/metal capacitors with W/ZnO:B/W structure.
• Optical characterization to determine optical band gap and transmittance.
• Electrical characterization including current-voltage (I-V) measurements at various temperatures.
• Analysis of resistance switching behavior (nonpolar, resistance ratio).
• Investigation of conduction mechanisms in high resistance state (HRS) and low resistance state (LRS).

Main Results:

• ZnO:B films exhibited an optical band gap of ~3.26 eV and ~91% transmittance in the visible light region.
• The W/ZnO:B/W structure demonstrated nonpolar resistance switching.
• A high resistance ratio of approximately 10⁵ between HRS and LRS was achieved at room temperature.
• Hopping conduction dominated in HRS, while Ohmic conduction prevailed in LRS.
• Trap spacing of 1.2 nm and trap energy levels in ZnO:B films were determined.

Conclusions:

• Transparent boron-doped zinc oxide is a viable material for nonpolar resistance switching memory.
• The observed high resistance ratio and distinct conduction mechanisms are beneficial for memory applications.
• The ability to determine trap parameters provides insights into the switching physics and material optimization.