We have used a simple, analytically solvable model to analyze the characteristics of dual-gate metal-oxide-semiconductor field-effect transistors (MOSFETs) with 10 nm-scale channel lengthL. The model assumes ballistic dynamics of two-dimensional electrons in an undoped channel between highly doped source and drain. When applied to siliconn-MOSFETs, calculations show that the voltage gain (necessary for logic applications) drops sharply atL∼10 nm,while the conductance modulation remains sufficient for memory applications untilL∼4 nm.©1997 American Institute of Physics.