Fabrication of Novel Three-Step Drift-Doped Low-Temperature Polycrystalline Silicon Lateral Double-Diffusion Metal-Oxide-Semiconductor Using Excimer Laser Crystallization

摘要

Low-temperature polycrystalline silicon (poly-Si) thin-film transistor lateral double-diffusion metal-oxide-semiconductor field-effect transistors (LTPS TFT LDMOSFETs) and lateral insulated-gate bipolar transistors (LIGBTs) were fabricated by combining a thin-film transistor with a power structure, three-step drift doping, and excimer laser annealing. The maximum breakdown voltage of the three-step drift-doped LTPS-LDMOS after excimer laser annealing is 286 V with a 35μm drift region length (L_(drift)). The specific on-resistance is low (approximately 9 Ω cm~2) and the ON/OFF current ratio is about 1.28 × 10~6 with L_(drift) = 15μm. The subthreshold swing (SS) is about 1 V/ decade. Comparing the three-step drift-doped LDMOS with the three-step drift-doped LIGBT under the same processing conditions clearly indicates that the breakdown voltage and current capacity of LIGBT exceeds those of LDMOS.