Fig. 5: Channel length scaling and variability of NO-doped 1L-We2 FETs.
From: Uncovering the doping mechanism of nitric oxide in high-performance P-type WSe2 transistors
a–d Distribution of transfer characteristics ID-VG of pristine (light-color) and NO-doped (dark-color) 1L-WSe2 p-FETs with channel lengths of 55 nm (a), 180 nm (b), 380 nm (c) and 780 nm (d) at VDS = –1 V. e Optical microscopy (OM) of large transistor arrays. Scale bar: 100 μm. f–h Boxplots with Gaussian fitting of key device metrics, including VTH, LIN, SS, and ION at VOV = -0.5 V. VTH, LIN is extracted by linear extrapolation at the point of peak-transconductance. The color of the symbols corresponds to the channel length in a–d. For each group of data, a boxplot was created and Gaussian fitting was performed. The error bars represent the standard deviation of each distribution, as obtained from Gaussian fitting. The graphs show the mean (square symbols), standard deviation, lower quartile (25%), median (50%), upper quartile (75%), interquartile range (25–75%), and maximum and minimum (cross symbols). i A cross-sectional scanning transmission electron microscopy (STEM) image of one representative short channel 1L-WSe2 transistors, which feature a 6 nm HfO2 dielectric, 0.5/30/30 nm Ti/Pt/Au metal contacts, and a channel length of 55 nm. j Cumulative distribution function (CDF) plots of device metrics. From the left to right, threshold voltage (VTH, CC) extracted at a constant current of 10 pA/µm at VD = -0.1 V, the minimum subthreshold swing (SS), and maximum transconductance (gmax). k ID-VG of one representative 55 nm-long-channel device at VD = -1V. l Statistical bar graph of maximum current (Imax) from 150 devices. Gray colors denote pristine 1L-WSe2 p-FETs. Blue colors denote NO-doped 1L-WSe2 p-FETs, while green for the same devices after 24 days. The dashed horizontal line denotes the averaged Imax of p-FETs.
