A novel memory array is disclosed, the array utilizing a matrix of variable threshold insulated gate field effect transistor cells. The cells are comprised solely of a gate region, having nitride and oxide layers, and a source region with the output data sensed, at the source, as a change of source charge as distinguished from the prior art sensing of a change of low impedance source voltage. In operation, each cell functions as an alterable capacitor. A negative pulse applied to the gate selects the cell. Variations in stored charge at the nitride-oxide interface causes changes in the threshold voltage and effective capacitance of the cell. The source charge may then be sensed to read the stored data.