A method is outlined for the determination of a 2-dimensional solution of the potential distribution in the substrate of the m.o.s.t., based on the complete depletion-neutral approximation. Channel current is derived from a 1-dimensional solution of the continuity equation along the silicon-silicon dioxide interface, for given values of extrinsically applied electrode potentials. Theoretical characteristics have been validated by comparison with those of a practical device. A discussion of pinchoff is also included.