A novel observation of negative differential resistance in a standard CMOS transistor and its application to a compact frequency doubler

초록

Negative differential resistance (NDR)-in which current decreases with increasing voltage-represents nonlinear behavior in nanoscale devices, offering unique opportunities to probe carrier dynamics and field-matter interactions beyond conventional monotonic responses. While NDR has become a recurring feature in devices based on emerging materials, its occurrence in standard complementary metal-oxide-semiconductor (CMOS) transistors has been exceedingly rare. Achieving NDR within a CMOS-compatible platform is highly desirable, as it enables compact nonlinear functionalities without the need for multi-device circuits or additional biasing networks. Here we report the first experimental demonstration of two distinct NDR mechanisms in fully depleted silicon-on-insulator (FDSOI) transistors fabricated using an industry-standard CMOS process. At the drain terminal, a previously unreported NDR regime emerges at high drain bias due to hot-carrier injection into the drain-side dielectric, where localized trapping perturbs the electric field and suppresses impact ionization. In the body terminal, by contrast, NDR arises from the interplay of gate-induced drain leakage and lateral-field-enhanced impact ionization, achieving an unprecedented peak-to-valley ratio of 2.37 & times; 10(4) at 1.0 V with exceptional stability. Building on these findings, we demonstrate that the steep, low-voltage body-terminal NDR directly enables a reconfigurable frequency doubler within a single transistor. By linking terminal-specific transport dynamics to device-level nonlinear functions, this work establishes both a new physical framework for understanding NDR in silicon transistors and a CMOS-compatible route to compact, energy-efficient nonlinear circuit elements.

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