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This study demonstrates the integration of a thin film transistor (TFT) and resistive random-access memory (RRAM) to form a one-transistor-one-resistor (1T1R) configuration. With the concept of the current conducting direction in RRAM and TFT, a triple-layer stack design of Pt/InGaZnO/Al2O3 is proposed for both the switching layer of RRAM and the channel layer of TFT. This proposal decreases the complexity of fabrication and the numbers of photomasks required. Also, the robust endurance and stable retention characteristics are exhibited by the 1T1R architecture for promising applications in memory-embedded flat panel displays.

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In this work, the relation between post annealing temperature and electrical characteristic on high mobility a-IZTO TFTs was investigated. The 400℃-annealed a-IZTO TFTs exhibited a better performance with field effect mobility of 39.6 cm 2 /Vs, V th of -2.8 V and sub-threshold swing of 0.25 V/decade. Both shallow trap states of a-IZTO film and interface trap states at the a-IZTO/SiO 2 interface decreased to 2.16×10 17 cm -3 eV -1 and 4.38×10 12 cm -2 eV -1 , respectively with 400℃ annealing. Owing to the higher energy from annealing process, the structural relaxation can be enhanced leading a better electrical characteristic of a-IZTO TFTs. Figure 4. Hysteresis loop of (a) as-deposited, (b) 200℃annealed and (c) 400℃-annealed a-IZTO TFTs.

The Al-doped Author KeywordsAZTO; Schottky diode; resistive switching; RRAM; read margin. Objective and BackgroundIn recent years, transparent amorphous oxide semiconductors (TAOS) are highly received candidates for large-sized liquid-crystal displays (LCDs) and active-matrix organic light-emitting diode displays (AMOLEDs). It owns lots of desirable features, such as the high optical transparency, low processing temperature and high electron mobility even when it is deposited at room temperature without any thermal annealing processes [1,2]. Among several TAOS materials, the amorphous aluminum (Al)-doped zinc (Zn) tin (Sn) oxide (a-AZTO) is receiving great interests due to its low material cost, and its components free of indium (In) and gallium (Ga) which are rare elements on the Earth [3][4][5]. On the other hand, there have been many researches [6,7] about memory-in-pixel (MIP) circuit for low power consumption in LCDs. Besides, T. Nishijima et al reported the low-power display system through the non-volatile memory (NVM) array [8]. The RRAM devices are next-generation NVM alternative technologies owing to its simple device structure, low power consumption, favorable scalability and fast switching [9,10]. However, to implement high density 4F 2 cross point array, a non-linear selection device such as diode is needed to suppress the sneak current through the unselected cells which causes readout errors. In this work, we demonstrated all the a-AZTO material based one Schottky diode and one resistor (1D1R) configuration for high storage capacity, which is benefit for high resolution advanced active-matrix flat panel displays applications. MethodsA simple metal/insulator/metal (MIM) structure, which consisting of titanium (Ti)/AZTO/platinum (Pt) structures were fabricated at room temperature. Firstly, titanium oxide (TiO 2 ) was deposited to be a buffer layer by electron-gun (e-gun) evaporation process for enhancing the adhesion to a silicon substrate. Then, a 50 nm-thick Pt acting as a bottom electrode was also formed by the e-gun evaporation. It was followed that a 50 nm-thick AZTO resistive switching layer was deposited by radio-frequency (RF) magnetron sputtering with an AZTO ceramic plate target consisted of ZnO, SnO 2 and Al 2 O 3 (67:30:3 mol %). The Ar gas flow rate was set to 10 sccm, while the sputtering pressure and power was 3m Torr and 80 W, respectively. Finally, a 50 nm-thick Ti was deposited to form top electrodes. The size of the memory cell was patterned by shadow mask with a diameter of 0.2 to 0.6 mm. Electrical measurements were done by the Keithley 4200 semiconductor characterization analyzer. Fig. 1 shows the current-voltage (I-V) characteristics of the Ti/AZTO/Pt device. A good rectifying characteristic was observed with a rectification ratio I on/off of 10 6 at ±1 V, and also showing high forward bias current about 0.5 mA at 3V. In addition, The Ti/AZTO/Pt Schottky diode device is capable of being switched from the rectifying mode to the resistive-switching characteristics by ap...