Semiconductor devices and methods of making the devices are described. The devices can be junction field-effect transistors (JFETs) or diodes such as junction barrier Schottky (JBS) diodes or PiN diodes. The devices are made using selective ion implantation using an implantation mask. The devices have implanted sidewalls formed by scattering of normal or near normal incident ions from the implantation mask. Vertical junction field-effect transistors with long channel length are also described. The devices can be made from a wide-bandgap semiconductor material such as silicon carbide (SiC) and can be used in high temperature and high power applications.