ICMCTF2016 Session C5-3: Thin Films for Active Devices
Tuesday, April 26, 2016 8:00 AM in Room Sunset
Time Period TuM Sessions | Abstract Timeline | Topic C Sessions | Time Periods | Topics | ICMCTF2016 Schedule
C5-3-1 Resistive Switching Mechanism of Self-protective Compliance Current Characteristic on ITO/CuTe/TiN Conductive-Bridging RAM
Chih-Cheng Shih, Tsung-Ming Tsai, Ting-Chang Chang (National Sun Yat-Sen University, Taiwan, Republic of China)
A self-protective compliance current conductive bridge random access memory (CBRAM) device was produced by physical vapor deposition (PVD). The device structure was ITO/CuTe/TiN which insulator was a solid-state electrolyte. ITO electrode made the device form self-compliance I-V characteristic without selectors. To clarify the switching mechanism, conduction current fitting was applied to explore that resistance changed depend on dielectric constant rather than schottky distance by multi-reset process. Meanwhile, we were modeling to explain the characteristic that tellurium which was dissociated from solid-state electrolyte CuTe was stacking on ITO electrode. There was a resistor formed to protect the CBRAM device.
C5-3-2 Temperature and Humidity Dependent Mechanical Behavior of Ultra-low k Dielectric Materials
Anqi Qiu, David Vodnick (Hysitron, Inc., USA)
Ultralow k dielectric materials as one of implementations to the continuing scaling of microelectronic devices is used to maintain the low interconnect capacitance and high mechanical strength. Under a variety of circumstances, electronic devices undergo a wide range of temperature and humidity in working environment. Such that a cellphone manufactured in the cold winter of northern China should work functionally at 35C with 100% relative humidity in Singapore. To investigate the spectrum of mechanical behaviors of nanometer scale ULK films in the environment, we performed nanoindentation on 200nm Ultra-low k material from 5C -85C and 5-90% Relative Humidity. Cohesive fracture as well as indentation modulus is affected by the temperature and humidity. The mechanical properties of Ultralow k material will be discussed in detail.
C5-3-3 Effect Of Oxygen Partial Pressure on Deep-Level Defect Distribution in Sputtered ZnO Thin-Film Transistors
Jinhee Park, YouSeung Rim, Chao Li, MinhTrang Ha, HyungSeok Kim, Mark Goorsky, Dwight Streit (University of California, Los Angeles, USA)
We have found a direct correlation between the distribution of deep-level defect states in ZnO thin film transistors and the oxygen partial pressure used during RF sputtering. Photo-induced threshold voltage-shift measurements under monochromatic illumination were used to characterize the distribution of deep-level defect states in the sputtered ZnO transistors. The transistor films were grown using RF sputtering with a range of oxygen partial pressures. Deep-level defects in the 1.8 – 2.0 eV range below the conduction band minimum monotonically decreased with increasing oxygen partial pressure. We also observed in the ZnO films a concomitant reduction in oxygen vacancies associated with the O1s peak as measured by XPS. The effect of these oxygen-vacancy deep levels on transistor performance included threshold voltage shifts and increased photo-induced leakage currents under illumination, degrading the performance and stability of the sputtered ZnO transistors under visible light due to the photo-ionization of trapped charges. We determined that oxygen-rich conditions during the sputtering growth of ZnO thin film transistors effectively suppressed the deep-level defect states associated with oxygen vacancies.
C5-3-4 Characteristics of Hafnium Oxide Resistance Random Access Memory with Different Resetting Cut Voltage
Yu-Ting Su, Ting-Chang Chang, Tsung-Ming Tsai, Kuan-Chang Chang, Hsin-Lu Chen, Jhih-Cheng Yang (National Sun Yat-Sen University, Taiwan, Republic of China); Simon Sze (Stanford University, USA)
In this study, the dynamic switching behaviors of reset process on hafnium oxide based resistance random access memory during reset process were investigated by analysis of carrier conduction mechanism with change of operation electrical field. The distances and energy barrier height of effective switching gap were calculated from the results of current fitting based on the Schottky emission equation. According to the change of energy barrier height, we proposed a model to explain the geometric shapes of conduction path changed from tip to blunt during reset process. The model is also demonstrated by COMSOL Multiphysics electrical field simulation.
C5-3-5 Conduction Mechanism in Resistance Random Access Memory with Transparent Electrode under illumination
Chih-Hung Pan, Tsung-Ming Tsai, Ting-Chang Chang, Kuan-Chang Chang, Po-Hsun Chen (National Sun Yat-Sen University, Taiwan, Republic of China); Simon Sze (Stanford University, USA)
A light-sensitive RRAM device is investigated in this letter by introducing transparent indium tin oxide (ITO) as a top electrode. Owing to the oxygen deficient property of ITO, the position of the resistive switching layer is predefined due to the directional oxygen ions attraction. The effects of i llumination on electrical behaviors are discussed in detail and a conduction model is also established to explain the corresponding physical mechanism s . W e found that using ITO as an electrode can significantly modify the RRAM device working properties and the current conduction mechanisms. This research provides a better understanding of illumination effects for future application s of transparent RRAM devices.
C5-3-6 Mechanism of Low Operation Voltage with ITO RRAM
Chih-Yang Lin (National Sun Yat-Sen University, Taiwan, Republic of China); Lin-Yi Shih (National Kaohsiung Normal University, Taiwan, Republic of China); Ting-Chang Chang, Kuan-Chang Chang, Tsung-Ming Tsai, Chih-Hung Pan (National Sun Yat-Sen University, Taiwan, Republic of China); Jung-Hui Chen (National Kaohsiung Normal University, Taiwan, Republic of China); Yi-Ting Tseng (National Sun Yat-Sen University, Taiwan, Republic of China); Simon Sze (National Chiao Tung University, Taiwan, Republic of China)
Technological development for memory, logic IC, on-display devices and batteries is indispensable for advanced portable electronic products. Among all these devices, a reliable, fast-working, and energy-saving non-volatile memory especially for portable applications is extremely important. Resistance Random Access Memory (RRAM) has great potential to serve as a next-generation nonvolatile memory device due to its simple structure, low power consumption, rapid operation, and high density integration capability.
RRAM devices have been thoroughly investigated both for stand-alone memory and array applications, their power consumption is crucial to applications. RRAM devices have small operation voltage with enough on/off ratio will effectively reduce total power consumption. By determinate mechanism of low operation voltage RRAM will decrease power consumption of arrayed RRAM, it also can be operated by small transistors with low conduction current. In our experiment, we found the RRAM structure ITO/ITO(O2)/TiN have low operation voltage(-0.05V to +0.06V) with one order between on/off ratio. We find that is relate to oxygen distribution between ITO and ITO(O2) layer, analyzing electricity data by Schottky conduction formula. By comparing intercept and slope of Voltage - nature log Current diagram to another RRAM with Schottky conduction, we explained why RRAM with ITO/ITO(O2)/TiN structure have such small operation voltage.