Yes, the first DC power switch semiconductor was the SCR, though there you always had at least 2 of them, some really high value inductors, high power resistors and big capacitors to allow one SCR to be used to force commutate the other. But you could have a 200A SCR controlling a DC motor at around 100Hz PWM rate to allow variable speed control, which was a massive jump in efficiency over the previous method, which involved both multiple tappings off the battery bank and some serious power resistors to give stepped control. SCR you could use a single battery voltage, have control from near 0% to 100% with near stepless control, along with feedback so your motor speed was constant despite massive load variations. High voltage withstand when off, high current when on, and pretty much almost no switching loss in operation until you got into the audible frequency ranges, still the preferred device for ultra high power use, where IGBT devices are only now starting to get serious attention.