Maximum blocking voltages and dynamic turn-on processes of current switches based on GaAs/AlGaAs heterothyristors with the thickness of weakly doped region increased to 8 μm were investigated using numerical simulation methods within the framework of the quasi-one-dimensional drift-diffusion model. The influence of the design of the weakly doped region of the collector junction of the n-p-n transistor part while maintaining the total thickness of 8 μm was determined. It was shown that the maximum blocking voltage reaches ~180 V for the design of a composite p-base including a heavily doped layer (p=10¹⁸ cm^-3) with a thickness of 0.1 μm and a weakly doped layer (p=6·10¹⁴ cm^-3) with a thickness of 8 μm. It was shown that, regardless of the design, close values of the maximum turn-on current of ~70 A and the width of the turn-on fronts of ~1.5-1.6 ns are achieved. However, the best values of residual voltage and turn-on delay are achieved in the design with an n-collector of the n-p-n transistor part thinned to 0.2 μm and are ~1.86 V and 5.5 ns, respectively. Keywords: thyristor, current switch, drift-diffusion model, dynamics, turn-on front, residual voltage, turn-on delay.