The effects of MIC/MILC interface on the performance of MILC-TFTs

Kwok

IEEE Electron Device Lett.

1999

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Abstract-High-performance, low-temperature processed thinfilm transistors (TFT's) with ultrathin (30-nm) metal induced laterally crystallized (MILC) channel layers were fabricated and characterized. Compared with the MILC TFT's with thicker (100 nm) channel layers, the ones with the 30-nm channel layers exhibit lower threshold voltage, steeper subthreshold slope, and higher transconductance. Furthermore, the comparatively lower off-state leakage current and the higher on-state current of the "thin" devices also imply a higher on/off ratio. At a drain voltage of 5 V, an on/off ratio of about 3 2 10 7 was obtained for the 30-nm TFT's, which is about 100 times better than that of the 100-nm TFT's. No deliberate hydrogenation was performed on these devices.

Section: Resultsmentioning

confidence: 99%

Performance of thin-film transistors with ultrathin Ni-MILC polycrystalline silicon channel layers

Kwok

IEEE Electron Device Lett.

1999

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“…The behavior is typical of field effect TFT's showing partial saturation effects at high . The slight increase of at above 4.5 V is probably caused by grain boundary enhanced "kink" effects [11].…”

Section: Resultsmentioning

confidence: 99%

High-performance polycrystalline SiGe thin-film transistors using Al₂O₃ gate insulators

Kwok

IEEE Electron Device Lett.

1998

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Abstract-The use of aluminum oxide as the gate insulator for low temperature (600 C) polycrystalline SiGe thin-film transistors (TFT's) has been studied. The aluminum oxide was sputtered from a pure aluminum target using a reactive N 2 O plasma. The composition of the deposited aluminum oxide was found to be almost stoichiometric (i.e., Al 2 O 3 ), with a very small fraction of nitrogen incorporation. Even without any hydrogen passivation, good TFT performance was measured on devices with 50-nmthick Al 2 O 3 gate dielectric layers. Typically, a field effect mobility of 47 cm 2 /Vs, a threshold voltage of 3 V, a subthreshold slope of 0.44 V/decade, and an on/off ratio above 3 2 10 5 at a drain voltage of 0.1 V can be obtained. These results indicate that the direct interface between the Al2O3 and the SiGe channel layer is sufficiently passivated to make Al2O3 a better alternative to grown or deposited SiO2 for SiGe field effect devices.

“…This is manifested as current kinks in the - (Fig. 11) curves of the testing configuration with the MMGB self-aligned to the drain junction [25]. When the source and drain terminals are interchanged so that the MMGB is offset from the drain junction, the current kinks are suppressed.…”

Section: Device Characterizationmentioning

confidence: 95%

Characterization of the MIC/MILC interface and its effects on the performance of MILC thin-film transistors

IEEE Trans. Electron Devices

Bhat

et al. 2000

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112

Abstract-Process and material characterization of the crystallization of amorphous silicon by metal-induced crystallization (MIC) and metal-induced lateral crystallization (MILC) using evaporated Ni has been performed. An activation energy of about 2 eV has been obtained for the MILC rate. The Ni content in the MILC area is about 0.02 atomic %, significantly higher than the solid solubility limit of Ni in crystalline Si at the crystallization temperature of 500 C. A prominent Ni peak has been detected at the MILC front using scanning secondary ion mass spectrometry. The MIC/MILC interface has been determined to be highly defective, comprising a continuous grain boundary with high Ni concentration. The effects of the relative locations of this interface and the metallurgical junctions on TFT performance have been studied.Index Terms-Grain boundary, MILC, nickel, thin-film transistor.