Simple Analytical Bulk Current Model for Long-Channel Double-Gate Junctionless Transistors

A bulk current model is formulated for long-channel double-gate junctionless (DGJL) transistors. Using a depletion approximation, an analytical expression is derived from the Poisson equation to find channel potential, which expresses the dependence of depletion width under an applied gate voltage. The depletion width equation is further simplified by the unique characteristic of junctionless transistors, i.e., a high channel doping concentration. From the depletion width formula, the bulk current model is constructed using Ohm's law. In addition, an analytical expression for subthreshold current is derived. The proposed model is compared with simulation data, revealing good agreement. The simplicity of the model gives a fast and easy way to understand, analyze, and design DGJL transistors comprehensively.