Reliability characteristics and conduction mechanisms in resistive switching memory devices using ZnO thin films.

Fu-Chien Chiu,Peng-Wei Li,Wen-Yuan Chang

doi:10.1186/1556-276x-7-178

Abstract

In this work, bipolar resistive switching characteristics were demonstrated in the Pt/ZnO/Pt structure. Reliability tests show that ac cycling endurance level above 106 can be achieved. However, significant window closure takes place after about 102 dc cycles. Data retention characteristic exhibits no observed degradation after 168 h. Read durability shows stable resistance states after 106 read times. The current transportation in ZnO films is dominated by the hopping conduction and the ohmic conduction in high-resistance and low-resistance states, respectively. Therefore, the electrical parameters of trap energy level, trap spacing, Fermi level, electron mobility, and effective density of states in conduction band in ZnO were identified.

Highlights

Resistance random access memory [RRAM] has attracted a great deal of attention because of its good compatibility with the complementary metal-oxide semiconductor [CMOS] process, nonvolatility, low power consumption, low cost price, high switching speed, high durability, small cell size, simple cell structure, and multistate switching [1,2,3,4]
Since the RS depends on the polarity of applied voltage, the RS in Pt/ZnO/Pt structure is bipolar
Even both unipolar and bipolar RS may coexist in the Ag/ZnO/Pt structure [18]

Summary

Introduction

Resistance random access memory [RRAM] has attracted a great deal of attention because of its good compatibility with the complementary metal-oxide semiconductor [CMOS] process, nonvolatility, low power consumption, low cost price, high switching speed, high durability, small cell size, simple cell structure, and multistate switching [1,2,3,4]. The resistive switching characteristics and reliability were studied, the spacing between trap sites, the trap energy levels, as well as the electron mobility in ZnO films have not been addressed in detail. The behavior of bipolar resistive switching in Pt/ZnO/Pt metal-insulatormetal [MIM] structure was demonstrated.

Results

Conclusion