Scanning Capacitance Microscopy for Two-Dimensional Carrier Profiling of Semiconductor Devices

Nanoscale Probing of Electrical Memory Effects in van der Waals Layered PdSe2

“…As SMIM-C signals and capacitance–voltage characteristics are directly related to the charge carrier concentration, ,,, they can help interpret the dC/dV signals. In particular, a higher charge carrier concentration leads to a smaller change in the SMIM-C signal upon transition from depletion to accumulation . Furthermore, because the maps in Figure were obtained at zero DC voltage, this change in the capacitance signal seems to be a more reliable indicator of the charge concentration.…”

“…In particular, a higher charge carrier concentration leads to a smaller change in the SMIM-C signal upon transition from depletion to accumulation. 34 Furthermore, because the maps in Figure 3 were obtained at zero DC voltage, this change in the capacitance signal seems to be a more reliable indicator of the charge concentration. Therefore, we use the capacitance−voltage curves to calculate the maximum and minimum SMIM-C signals, as well as the signal difference (Figure 5).…”

“…Often, a lower dC/dV signal is associated with a higher charge carrier concentration, indicating contributions from more charge carriers at the NS that show a 0°phase (dark color) and the stack. 34,35 However, the interpretation of dC/ dV amplitude signals in SMIM and also in other techniques such as scanning capacitance microscopy can be complicated as the dC/dV signal is generally not monotonic as a function of charge carrier concentrations. 34,36,37 Both heavily doped and insulating materials are expected to show low dC/dV response.…”

“…34,35 However, the interpretation of dC/ dV amplitude signals in SMIM and also in other techniques such as scanning capacitance microscopy can be complicated as the dC/dV signal is generally not monotonic as a function of charge carrier concentrations. 34,36,37 Both heavily doped and insulating materials are expected to show low dC/dV response. 36 The dC/dV signal typically peaks at a certain concentration (around 10 17 −10 18 atoms/cm 3 ) and decreases for both higher and lower concentrations.…”

“…36 The dC/dV signal typically peaks at a certain concentration (around 10 17 −10 18 atoms/cm 3 ) and decreases for both higher and lower concentrations. 34,36,37 An increased dopant concentration can lead to a decreased dC/dV signal due to a lower thermal voltage and thinner depletion layer leading to a smaller change in capacitance as a function of voltage. 27,34 However, at concentrations below the peak, the dC/dV signal decreases with decreasing concentration because of other effects like a shift in the flat band voltage or a spreading resistance in series with the capacitance.…”