The ultra-short pulsed laser annealing process enhances the performance of MoS2 thin film transistors (TFTs) without thermal damage on plastic substrates. However, there has been insufficient investigation into how much improvement can be brought about by the laser process. In this paper, we observed how the parameters of TFTs, i.e., mobility, subthreshold swing, Ion/Ioff ratio, and Vth, changed as the TFTs’ contacts were (1) not annealed, (2) annealed on one side, or (3) annealed on both sides. The results showed that the linear effective mobility (μeff_lin) increased from 13.14 [cm2/Vs] (not annealed) to 18.84 (one side annealed) to 24.91 (both sides annealed). Also, Ion/Ioff ratio increased from 2.27 × 10 5 (not annealed) to 3.14 × 10 5 (one side annealed) to 4.81 × 10 5   (both sides annealed), with Vth shifting to negative direction. Analyzing the main reason for the improvement through the Y function method (YFM), we found that both the contact resistance (Rc) and the channel interface resistance (Rch) improves after the pulsed laser annealings under different conditions. Moreover, the Rc enhances more dramatically than the Rch does. In conclusion, our picosecond laser annealing improves the performance of TFTs (especially, the Rc) in direct proportion to the number of annealings applied. The results will contribute to the investigation about correlations between the laser annealing process and the performance of devices.

Recently, a shallow and conformal doping profile is required for promising 3D structured devices. In this study, we deposited the dopant phosphorus (P) using modified plasma assisted doping (PaD) followed by an annealing process to electrically activate the dopants. A rapid thermal annealing process (RTP) was the first approach tested for activation but it resulted in a deep junction (> 35 nm). To reduce the junction depth, we tried the flash lamp annealing process (FLP) to shorten the annealing time. We also predicted the annealing temperature by numerical thermal analysis, which reached 1,020 ℃. However, the FLP resulted in a deep junction (~ 30 nm), which was not shallow enough to suppress SCEs. Since an even shorter annealing process was required to form a USJ, we tried the laser annealing process (LAP) as a promising alternative. The LAP, which had a power density of 0.3 J/cm 2 , increased the surface temperature up to 1,100 ℃ with a shallow isothermal layer. Using the LAP, we achieved a USJ with an activated surface dopant concentration of 3.86×10 19 cm-3 and a junction depth of 10 nm, which will allow further scaling-down of devices.

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