This article proposes a compact trench-assisted space-modulated junction termination extension (TSM-JTE) design for high-voltage 4H-silicon carbide (SiC) devices. In this design, trench structures are introduced into the JTE region to effectively split the termination region into three functional zones. The proposed termination structure is cost effective in terms of the chip area it occupies; for devices rated at 10 kV, the termination structure extends the edge of the device by only 250 μm. Requiring only one implant, it is relatively cheap to fabricate, while a wide implantation dose window endures that is relatively insensitive to variations in dose that may occur during processing. The same advantages occur at 20 kV, the TSM-JTE proving to have the best tradeoff between maximum breakdown voltage and implantation window, compared with other single implant termination designs, achieving this in 500 μm of termination length. At 3.3 kV, a 110-μm TSM-JTE retains its advantages over the other JTE designs, but floating field rings are expected to consume less area, though this is not the case at the higher voltages.