Self-Aligned Metal Double-Gate Low-Temperature Polycrystalline Silicon Thin-Film Transistors on Non-Alkali Glass Substrate Using Diode-Pumped Solid-State Continuous Wave Laser Lateral Crystallization

Abstract

Self-aligned top and bottom metal double-gate (SAMDG) low-temperature polycrystalline silicon (poly-Si) thin-film transistors (TFTs) were fabricated on non-alkali glass at 550°C, using the diode-pumped solid-state continuous wave laser lateral crystallization (CLC) method. It was observed that the current drivability of SAMDG CLC poly-Si TFTs was eight or nine times larger than that of conventional top-gate excimer-laser-crystallized poly-Si TFTs, and the nominal field-effect mobility of the SAMDG CLC poly-Si TFT was larger than that of (100)-oriented single-crystal SIMOX-TFTs. In addition, a steep subthreshold value, 89 mV/dec, was observed for SAMDG CLC poly-Si TFTs. The exceptional high performance of SAMDG CLC poly-Si TFTs will allow the production of inexpensive LSI circuits on non-alkali glass substrates.