Read Characteristics of Independent Double-Gate Poly-Si Nanowire SONOS Devices

This paper investigates the read operation of poly-Si nanowire silicon-oxide-nitride-oxide-silicon devices with independent double-gate (IDG) configuration. The device features oxide-nitride-oxide (ONO) stack as the charge storage medium in one of the two gated sides with pure oxide in the other. Owing to the IDG feature, the shift in the device´s transfer characteristics due to a change in the amount of storage charges can be sensed with two different modes, which have one of the two gates applied with a sweeping bias (driving gate) and the other with a fixed bias (control gate). Our analysis and experimental data show that a larger memory window is obtained when the gate of the ONO side is used as the driving gate. Moreover, the memory window of this mode is essentially independent of the bias applied to the control gate. Based on this finding, a novel Flash structure featuring IDG cells with a common control gate is proposed.