Sung-Hoi Hur

A physical-based analytical turn-on model of polysilicon thin-film transistors for circuit simulation

A physical-based analytical current model of poly-Si thin film transistors (TFTs) for circuit simulation is presented. The model includes the barrier potential at grain boundaries, drain induced grain barrier lowering (DIGBL), temperature dependence, and the kink effect. The basic equation in the model has an analytic form for implementation in circuit simulators. The model has simple relationships between model parameters and device or material parameters. In addition to the current model, a capacitance model based on the current model is presented. Comparisons between the model and measured results show excellent agreement over wide ranges of operating voltages and for devices with different channel lengths.

Highly reliable polysilicon oxide grown by electron cyclotron resonance nitrous oxide plasma

Highly reliable inter-polysilicon oxide (polyoxide) for nonvolatile memory applications has been achieved using electron cyclotron resonance (ECR) N/sub 2/O-plasma. It is demonstrated that the N/sub 2/O-plasma polyoxide grown on doped poly-Si has a low leakage current and high breakdown field due to a smooth polyoxide/poly-Si interface and nitrogen incorporation during oxidation. Moreover, the polyoxide has much less electron trapping and over one order larger charge-to-breakdown (Q/sub bd/) up to 10 C/cm/sup 2/ than thermal polyoxide. The N/sub 2/O-plasma polyoxide can be a good choice for the interpoly dielectric of nonvolatile memories.

Oxidation of Silicon Using Electron Cyclotron Resonance Nitrous Oxide Plasma and Its Application to Polycrystalline Silicon Thin Film Transistors

Electron cyclotron resonance nitrous oxide (N 2 O) plasma oxidation has been investigated as a process to grow thin oxide on polycrystalline silicon and (100), (111), and (110) oriented crystalline silicon. In spite of a low thermal budget, N 2 O plasma oxidation incorporates nitrogen atoms at the silicon/silicon dioxide interface and forms a nitrogen-rich layer. The incorporated nitrogen atoms are tightly bound to silicon atoms at the interface with N (Is) electron energy of 397.8 eV. The oxidation rate in N 2 O plasma is less dependent on crystalline orientation in comparison with thermal O 2 , and is therefore nearly identical in poly- and single-crystalline-Si. Polysilicon oxide (polyoxide) grown by N 2 O plasma oxidation exhibits better electrical properties than thermally grown oxides; this is attributed to the smooth interface between the polyoxide and a poly-Si film. Polysilicon thin film transistors fabricated with N 2 O plasma oxide show improved performance, which is attributed not only to the smooth interface but also to oxygen- and nitrogen-plasma passivation.

A poly-Si thin-film transistor EEPROM cell with a folded floating gate

A new polysilicon thin-film transistor (poly-Si TFT) EEPROM with the folded floating gate structure has been proposed to suppress the field dependent leakage current at the programmed state. The control gate folds the floating gate and acts as a field plate to reduce the leakage current. As a result, the leakage current is maintained to the minimum level at an off-state control gate bias, irrespective of the programmed state, which is confirmed by simulation and experimental results. The fabricated poly-Si TFT EEPROM shows successful programming/erasing operation with a threshold voltage shift of 1 V after 5/spl times/10/sup 4/ program and erase cycles.

A physical-based analytical turn-on model of polysilicon thin film transistors for circuit simulation

A physical-based analytical current model of poly-Si TFTs for circuit simulation is presented. The model includes the barrier potential at grain boundaries, drain induced grain barrier lowering (DIGBL), temperature dependence, and the kink effect. The basic equation in the model has an algebraic form for implementation in circuit simulators. The model has the advantages of: simple relations between the model parameters and the device or material parameters; and ease of implementation in circuit simulators. In addition to the current model, a capacitance model based on the current model is presented. Comparisons between the model and measured results show excellent agreements in the wide range of operating voltages and for devices with different dimensions.

Suppressed short-channel effects and improved stability in polysilicon thin film transistors with very thin ECR N/sub 2/O-plasma gate oxide

Short-channel polysilicon thin film transistors with very thin (12 nm) electron cyclotron resonance N/sub 2/O-plasma gate oxide are investigated. Short-channel effects are drastically suppressed using ECR N/sub 2/O-plasma gate oxide. The fabricated n-channel TFTs exhibit a very small threshold voltage shift (<50 mV) and ON current change (<3%) after an electrical stress of 2/spl times/10/sup 4/ sec with Vgs=Vds=5 V.

Hydrogen passivation effects on performance of visible thin-film light-emitting diodes (TFLEDs)

The effects of hydrogen passivation on the performance of visible thin-film light-emitting diodes (TFLEDs) have been investigated. The TFLED with hydrogen passivation exhibits lower threshold voltage (by about 3 V), higher brightness (about 33 times), and much shorter electroluminescence (EL) peak wavelength (from 704.5 nm to 600 nm) and higher EL intensity than that without hydrogen passivation.