a‐InGaZnO thin‐film transistors for AMOLEDs: Electrical stability and pixel‐circuit simulation

Abstract

Abstract— Inverted‐staggered amorphous In‐Ga‐Zn‐O (a‐InGaZnO) thin‐film transistors (TFTs) were fabricated and characterized on glass substrates. The a‐InGaZnO TFTs exhibit adequate field‐effect mobilities, sharp subthreshold slopes, and very low off‐currents. The current temperature stress (CTS) on the a‐InGaZnO TFTs was performed, and the effect of stress temperature (TSTR), stress current (ISTR), and TFT biasing condition on their electrical stability was investigated. Finally, SPICE modelling for a‐InGaZnO TFTs was developed based on experimental data. Several active‐matrix organic light‐emitting‐display (AMOLED) pixel circuits were simulated, and the potential advantages of using a‐InGaZnO TFTs were discussed.

P.4: A Charge‐Cyclic Digital‐to‐Analog Converter for IGZO TFT Integrated Data Driver

“…TABLE 1 demonstrates the results from the fabricated devices. Then, the default parameters of RPI model were adjusted accordingly to fit the measurements [8]. Figure 3 shows the comparison between the experimental and simulated I-V characteristic for IGZO TFTs.…”

Pixel Circuit with Threshold Voltage Compensation using a-IGZO TFT for AMOLED

“…The threshold voltage of LTPS TFTs differs among pixels due to the random distribution of grain boundaries in the polysilicon material, resulting in a non-uniform gray-scale over the display area [5,6]. Consequently, TFTs based on other semiconductor materials have been evaluated as an alternative approach to realizing reliable, high-resolution and low cost AMOLEDs [7]. First of all, amorphous indium-galliumzinc-oxide (a-IGZO) TFTs have attracted special attention as an alternative to a-Si:H and LTPS TFTs due to the adequate field-effect mobility, high current on-off ratio, low off-current, a low processing temperature, visible transparency, a sharp sub-threshold swing, and potentially better electrical stability, which makes the a-IGZO TFT much more suitable to use in AMOLED displays [8][9][10][11][12][13].…”

P‐14: a‐IGZO TFT Based Pixel Circuits for AM‐OLED Displays

“…We can see that the RPI a-Si:H TFT model with appropriate a-InGaZnO TFT SPICE parameters can reproduce very well our measured device characteristics. SPICE parameters were extracted based on experimental data reported in [6,7], and summarized in Table 1. The OLED area was assumed to be 4563μm 2 which is about the subpixel area of an RGB 4.3" WVGA display (39μm x 117μm).…”