Backscattered Electrons from a Drain Region in a Silicon Decanano Diode

Abstract

We have systematically and quantitatively studied the properties and effect of the backscattered electrons from the drain region of a silicon (Si) decanano diode in order to investigate the backscattering effect on the characteristics of a Si decanano device. An ensemble Monte Carlo (EMC) simulation is employed, in which the scattering effect with backscattered electrons from the drain region is taken into account. The results of the numerical experiment revealed the following remarkable conclusion. The density ratio of the backscattered electrons to all electrons in the channel becomes large when the channel length is as short as or less than 20 nm. The average position of the backscattered electrons normalized by the channel length moves closer towards the source side as the channel length becomes short. The backscattering effect on the drain current strongly depends on the channel length rather than the drain voltage. When the channel length is more than 40 nm, the backscattered electrons do not affect the drain current at all. The backscattering effect on the drain current is more enhanced when the channel length is as short as or less than 40 nm and when the drain voltage is also small. Furthermore, a design guide for avoiding the effect of backscattering on the drain current is presented for the first time. We believe that it becomes more important to analyze the backscattering phenomenon from the drain region along with the miniaturization of the decanano device.