Temperature dependence of triodelike JFET drain current after pinchoff

The drain current of a triodelike JFET exhibits both positive and negative temperature dependence, depending on the current density. For drain current smaller than ∼5 A.cm^-2, the thermionic-injection mechanism prevails, leading to the positive temperature coefficient. On the other hand, a space-charge-limited current flows in the case of current density larger than ∼10 A.cm^-2, resulting in nearly T^-1dependence due to the mobility decrease.