Author_Institution :
State Key Lab., Hong Kong Univ. of Sci. & Technol., Hong Kong, China
Abstract :
In this paper, dc-stress-induced degradation in bridged-grain (BG) polycrystalline silicon (poly-Si) thin-film transistors (TFTs) is systemically characterized and investigated. Compared with normal poly-Si TFTs, BG poly-Si TFTs exhibit better hot-carrier (HC) reliability, better self-heating (SH) reliability, and better negative bias temperature (NBT) instability. Resulting from the heavily doped BG lines inside the active channel, lateral electric field reduction at the drain side, Joule heat diffusion enhancement at the channel length direction, and boron-hydrogen bond formation at interface/grain boundaries are, respectively, responsible for the improved HC reliability, SH reliability, and NBT reliability in BG poly-Si TFTs. In addition, stress Vg-dependent HC degradation with fixed stress Vd, stress power density-dependent SH degradation, and vertical electrical field-dependent NBT degradation are also examined in both normal poly-Si TFTs and BG poly-Si TFTs. All test results indicate that such high-performance and highly reliable BG poly-Si TFT has a great potential for system-on-panel application.
Keywords :
crystal defects; grain boundaries; hot carriers; negative bias temperature instability; semiconductor device breakdown; semiconductor device reliability; silicon; stress analysis; thin film transistors; BG polySi TFT; DC-stress-induced degradation; HC degradation; HC reliability; Joule heat diffusion enhancement; NBT instability; SH reliability; active channel; boron-hydrogen bond formation; bridged-grain polycrystalline silicon thin-film transistor; channel length direction; grain boundary; hot-carrier reliability; interface boundary; lateral electric field reduction; negative bias temperature; self-heating reliability; stress power density-dependent SH degradation; system-on-panel application; vertical electrical field-dependent NBT degradation; Degradation; Logic gates; Semiconductor device reliability; Silicon; Stress; Thin film transistors; Bridged grain (BG); hot carrier (HC); negative bias temperature instability (NBTI); polycrystalline silicon (poly-Si); self-heating (SH); thin-film transistors (TFTs);
