  We report raster scan multiplexed charge-stability diagram measurements for
tuning multiple gate-defined quantum dots in GaAs/AlGaAs heterostructures. We
evaluate the charge sensitivity of the quantum point contact (QPC) in both
radio frequency (rf)-reflectometry and direct current (dc)-transport modes,
where we measure the signal-to-noise ratio (SNR) of 40 for rf-QPC with
integration time per pixel of 10ms , corresponding to 1.14ms for resolving
single electron transition in few electron regime. The high SNR for reasonable
integration time allows fast two-dimensional (2D) scanning, which we use to
facilitate double and triple quantum dot tuning process. We configure highly
stable raster scan multiplexed quantum dot tuning platform using a switching
matrix and transformer-coupled alternating current (ac) ramp sources with
software control. As an example of high-throughput multiple quantum dot tuning,
we demonstrate systematic triple quantum dot (TQD) formation using this
platform in which a multiplexed combination of 2D scans enables the
identification of few electron regime in multiple quantum dots in just a few
minutes. The method presented here is general, and we expect that the tuning
platform is applicable to more complex multiple quantum dot arrays, allowing
efficient quantum dot system Hamiltonian parameter calibration.
