UFDG

The process/physics-based UFDG model is generic, being applicable to asymmetrical as well as symmetrical double-gate (DG) UTB MOSFETs, to single-gate fully depleted (FD) SOI UTB MOSFETs with relatively thick back, or buried oxide (BOX), and to independent-gate DG structures. The model is based on an self-consistent solution of the Schrodinger and Poisson equations in the thin Si-film body/channel of the DG or FD/SOI device. It is, in essence, a compact Poisson-Schrodinger solver in a circuit simulator. A variational approach, using a general description of the wavefunction, is used to solve the Schrodinger equation, which is linked to Poisson's equation via Newton-Raphson iteration. Use of 2D density of states, with proper effective masses (defined by the Si surface orientation), and Fermi-Dirac statistics then characterizes the inversion charge density and distribution in all the significant subbands for arbitrary gate biases. The quantization (QM) modeling includes dependences on Si-film thickness (t_Si) as well as transverse electric field (E_x). The carrier transport and channel current are modeled as quasi-ballistic via an accounting for velocity overshoot, derived from the Boltzmann transport equation and its moments, and a QM-based characterization of mobility as a function of t_Si and E_x as well. UFDG is charge-based, with the terminal charge modeling physically linked to the current modeling. It has been verified by numerical device simulations and test-device data.

A UFDG user's license can be obtained from the University of Florida, as noted on the home page of this web site.