TFT_ex15.in : AMOLED Pixel Simulation

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TFT_ex15.in : AMOLED Pixel Simulation

Every software package contains a full set of examples suitable for that version and are installed with the software. If you see examples here that are not in your installation you should consider updating to a later version of the software. These examples can be used by beginners and advanced users for product evaluation, teaching purposes, and self-training.

Required Modules

Victory Device:

2D Simulator
2D TFT
2D MixedMode
2D Organic

In this example, we made a simple pixel circuit which is driven by two transistor and one capacitor. The OLED (Organic Emitting Diode) is directly connected to Vdd and drain side of driving n-TFT transistor so that data voltage (Vdata) is proportional to Vgs of driving TFT (Vdata = Vgs). Both the OLED structure and the a-Si TFT (bottom gate back channel etch TFT) are made by Victory Device. User can make a circuit (netlist) by MixedMode syntax, which is the same as spice netlist. Finally, MixedMode simulates the OLED pixel current by applying data voltage with fixed “select ” voltage. In this study, the data voltage with vselect=15 V are plotted. User can change selection voltage 10V or 5V to compare with the published data [1].

DEVICE SIMULATION 1 Makes a-Si TFT Structure.

This part makes a mesh structure of a-Si TFT (bottom gate back channel etch TFT) and saves it as *_TFT.str file. This structure is used for switching and driving TFTs in mixedmode circuit simulation.

DEVICE SIMULATION 2 Makes OLED Structure.

This part makes a mesh structure of 2-layer OLED and saves *_OLED.str file. It consists of TPD for hole transport layer and Alq3 for electron transport layer as well as light emitting material. The anode is connected to “Vdd ” and the cathode is contacted with “drain ” side of the driving TFT.

DEVICE SIMULATION 3 AMOLED pixel simulation by using MixedMode.

The pixel circuit is described in between .BEGIN and .END. The mesh structure is loaded into MixedMode by infile= “* ” in “Axxx ” statements. .LOG saves simulated curve data. .DC solve the circuit when data node is ramped up to 15 V. Each device is defined as device=aoled and device=atft1/atft2 to assign different physical model. Victory Device/MixedMode solve simultaneously terminal current/voltage in numerical device as well as circuit nodal voltage/current in circuit part.

Reference:
[1] Bahman Hekmatshoar, Alex Z. Kattamis, Kunigunde Cherenack, Sigurd Wagner and James C. Sturm, “A novel TFT-OLED integration for OLED-independent pixel programming in amorphous-Si AMOLED pixels, ” in Journal of the Society for Information Display, Volume 16, Issue 1, page 183-188, June 2012, doi: 10.1889/1.2835027.