Fabrication and characterization of a VMOS EPROM

This paper presents experimental results for the performance of the VMOS EPROM device. The fabrication of the device is presented, followed by data for programmability and data retention. The device programs with lower applied voltages than other EPROM devices, and its projected data retention characteristic predicts a threshold drop of less than 1 volt in 40 years at 150°C junction temperature. EPROM device modeling for use in circuit simulation is also presented. Methods to calculate the capacitors associated with the device are shown for the VMOS geometry, and it is shown that no weak-inversion current exists due to drain coupling.