Passivation kinetics of two types of defects in polysilicon TFT by plasma hydrogenation

Bias temperature instability comparison of CMOS LTPS-TFTs with HfO2 gate dielectric

“…1. The degradation of subthreshold swing S.S. is attributed to the generation of the interface trap states N it of HfO 2 /poly-Si [15][16][17][18][19], which both NBTI and PBTI could degrade the HfO 2 /polySi interface. In addition, the increase of threshold voltage |DV TH | can be attributed to not only the degradation of subthreshold swing S.S. but also the oxide charge trapping in HfO 2 [19].…”

“…Higher temperature of PBTI for n-type device shows more transconductance G m degradation and later saturation time of G m degradation, and the NBTI of p-type device shows much enhanced degradation rate with the increased temperature. The transconductance G m of polySi TFTs is strongly related to the tail-trap states located near the band edge of poly-Si in the HfO 2 /poly-Si interface and the grain boundaries of poly-Si near the surface conduction channel [16][17][18][19]. The saturated G m degradation of PBTI of n-type device indicates the generation of tail-trap states near the conduction band by PBTI is saturated, and the continuous G m degradation of NBTI for p-type device indicates the generation of tail-trap states near the valence band by NBTI is enhanced.…”

“…The saturated G m degradation of PBTI of n-type device indicates the generation of tail-trap states near the conduction band by PBTI is saturated, and the continuous G m degradation of NBTI for p-type device indicates the generation of tail-trap states near the valence band by NBTI is enhanced. In addition, the subthreshold swing S.S. of poly-Si TFTs is strongly related to the deep-trap states located near the midgap of poly-Si in the HfO 2 /poly-Si interface and the grain boundaries of poly-Si near the surface conduction channel [16][17][18][19]. Although the transconductance G m degradation of PBTI for n-type device shows a saturated behavior, the subthreshold swing S.S. degradation of PBTI doesn't, which is shown in Fig.…”

Effects of the single and double (overlap) scanned excimer laser annealing on solid phase crystallized silicon films

“…Previous reports have connected the TFT field-effect mobility to the density of trap states close to the conduction and valence bands (tail states), whereas the threshold voltage and the sub-threshold slope seem to be more sensitive to the deep states near midgap [9,10]. Tail states are believed to emanate mostly from the defects within the grains of the poly-Si [11] while deep states are typically related to grain-boundary defects, especially dangling bonds [9,12]. If the overlapped irradiation does not change the TFT characteristics, it is very useful because the length of the beam will not limit the available panel size.…”

High performance poly-Si thin film transistors fabricated by self-aligned seed induced lateral crystallization

“…The ELA method has meanwhile been developed in order to achieve high performance TFTs, [3] but the problems of non-uniform crystalline quality and high production cost have yet to be resolved. In contrast, metal-induced crystallization (MIC) or metal-induced lateral crystallization (MILC) methods require a lower thermal budget and present better on-state electrical performances than the SPC method [4][5][6][7] and lower cost than the ELA method. With MILC, Ni islands are selectively deposited on top of a-Si films and allowed to crystallize at a temperature below 600°C.…”