a short channel. High-speed, high-voltage switching with JFETs became technically feasible following the commercial introduction of Silicon carbide (SiC) wide-bandgap devices in 2008. Due to early difficulties in manufacturing — in particular, inconsistencies and low yield — SiC JFETs remained a niche product at first, with correspondingly high costs. By 2018, these manufacturing issues had been mostly resolved. By then, SiC JFETs were also commonly used in conjunction with conventional low-voltage Silicon MOSFETs. In this combination, SiC JFET + Si MOSFET devices have the advantages of wide band-gap devices as well as the easy gate drive of MOSFETs. Structure The JFET is a long channel of semiconductor material, doped to contain an abundance of positive charge carriers or holes (p-type), or of negative carriers or electrons (n-type). Ohmic contacts at each end form the source (S) and the drain (D). A pn-junction is formed on one or both sides of the channel, or surrounding it using a region with doping opposite to that of the channel, and biased using an ohmic gate contact (G). Functions JFET operation can be compared to that of a garden hose. The flow of water through a hose can be controlled by squeezing it to reduce the cross section and the flow of electric charge through a JFET is controlled by constricting the current-carrying channel. The current also depends on the electric field between source and drain (analogous to the difference in pressure on either end of the hose). This current dependency is not supported by the characteristics shown in the diagram above a certain applied voltage. This is the saturation region, and the JFET is normally operated in this constant-current region where device current is virtually unaffected by drain-source voltage. The JFET shares this constant-current characteristic with junction transistors and with thermionic tube (valve) tetrodes and pentodes. Constriction of the conducting channel is accomplished using the field effect: a voltage between the gate and the source is applied to reverse bias the gate-source pn-junction, thereby widening the depletion layer of this junction (see top figure), encroaching upon the conducting channel and restricting its cross-sectional area. The depletion layer is so-called because it is depleted of mobile carriers and so is electrically non-conducting for practical purposes. When the depletion layer spans the width of the conduction channel, pinch-off is achieved and drain-to-source conduction stops. Pinch-off occurs at a particular reverse bias (VGS) of the gate–source