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

Abstract

In this work, metal/oxide/metal capacitors were fabricated and investigated using transparent boron doped zinc oxide (ZnO:B) films for resistance switching memory applications. The optical band gap of ZnO:B films was determined to be about 3.26 eV and the average value of transmittance of ZnO:B films was about 91% in the visible light region. Experimental results indicated that the resistance switching in the W/ZnO:B/W structure is nonpolar. The resistance ratio of high resistance state (HRS) to low resistance state (LRS) is about of the order of 105 at room temperature. According to the temperature dependence of current-voltage characteristics, the conduction mechanism in ZnO:B films is dominated by hopping conduction and Ohmic conduction in HRS and LRS, respectively. Therefore, trap spacing (1.2 nm) and trap energy levels in ZnO:B films could be obtained.

Understanding of Selector‐Less 1S1R Type Cu‐Based CBRAM Devices by Controlling Sub‐Quantum Filament

“…It is reported that for Φ T >> Φ ξ , the hopping conduction current increases with increasing temperature ( Figure S5c, Supporting Information). [25] Following the same trend, the hopping conduction current increases in sub-quantum CBRAM devices, as shown in Figure 5d. The estimated activation energy is ≈ 310 meV, further confirms the deeper labels of defect sites.…”

“…reported that hopping conduction is the dominating mechanism for an electric field over 0.2 MV cm −1 . [ 25 ] If J is the current density, ξ is the electric field, q is the electronic charge, δ is the hopping distance between nearest neighbors or trap spacing, η is the e’ concentration in conduction band, γ is the vibration frequency, T is the absolute temperature, k is the Boltzmann's constant, Φ T is the trap energy level, then the hopping conduction can be expressed as …”

Status and Prospects of ZnO-Based Resistive Switching Memory Devices

“…Nevertheless, controlled deposition parameter and post-thermal treatment on resistive layer may be not as effective as doping technique to fully adjust the defect concentration. Various dopant elements, such as Al [ 137 , 175 , 176 ], B [ 177 ], Co [ 138 , 139 , 169 , 178 ], Cr [ 110 , 158 ], Cu [ 87 , 140 , 179 ], Fe [ 180 , 181 ], Ga [ 112 , 182 , 183 ], La [ 144 ], Li [ 184 , 185 ], Mg [ 55 , 111 , 145 , 186 – 190 ], Mn [ 91 , 146 – 148 , 191 – 195 ], N [ 56 , 149 ], Ni [ 196 ], S [ 197 ], Sn [ 90 , 198 ], Ta [ 199 ], Ti [ 150 , 151 ], V [ 85 ], and Zr [ 86 ], that have been reported may exhibit decent switching performance. ZnO-based RRAM with multi-element doping, such as Al-Sn [ 136 , 200 ], Ga-Sn [ 201 ], and In-Ga [ 141 – 143 , 202 – 208 ], is also proposed.…”

“…Employing an amorphous resistive layer may also avoid the formation of excessive and branching of CF due to the lack of grain boundary structure. Several efforts have been reported to fabricate amorphous ZnO-based RRAM, such as by doping [ 90 , 141 – 143 , 177 , 198 , 201 – 203 , 205 – 208 ], hydrogen peroxide treatment [ 183 ], and deposition parameter optimization [ 132 ].…”

Trap Exploration in Amorphous Boron-Doped ZnO Films

“…Recently, ZnO-based diluted magnetic semiconductors showed ferromagnetism in ZnO by doping with boron or a transition metal, which is promising to achieve practical Curie temperature for future spintronic devices [ 3 , 4 ]. In addition, transparent boron-doped ZnO (ZnO:B) films sandwiched between two tungsten electrodes showed memristive behavior, which is attractive to overcome the physical limitations of traditional Flash memory for the next generation nonvolatile memory applications [ 10 ].…”