Frequency Doubler Based on Ferroelectric Tunnel Field-Effect Transistor

In this study, a frequency doubler that consists of a ferroelectric tunnel field-effect transistor (FeTFET) is proposed, and its operation is verified using technology computer-aided design (TCAD) simulations. The proposed FeTFET has bidirectional tunneling currents, and the threshold voltage ( ${V}_{TH}$ ) of each current can be adjusted by local polarization in the ferroelectric layer. Therefore, the source-to-channel ( ${I}_{SC}$ ) and channel-to-drain currents ( ${I}_{CD}$ ) can be independently modulated by the specific program condition, and the symmetrical matching of ${I}_{SC}$ and ${I}_{CD}$ can be implemented by source- $/$ drain-side ${V}_{TH}$ adjustment. Through the mixed-mode circuit simulations, it is confirmed that the output frequency is doubled compared with that of the input sinusoidal signal by symmetrical matching of the bidirectional currents. Consequently, the proposed device is expected to be advantageous for circuit design and low operating power applications compared with conventional frequency doublers.