Transformable Junctionless Transistor (T-JLT)

Abstract

A conductivity type transformable junctionless transistor (T-JLT) is proposed. Two complementary doped, i.e., n- and p-type, polysilicon films thinner than 5 nm are arranged orthogonally with a dielectric in between, where each film plays a role as a source, a channel, a drain, and a gate, respectively. The role of the film is interchangeable by contact allocation. By swapping the contact assignment, the n- and p-type transistors attain the given device structure. This versatility reduces approximately four or two ion implantations and the associated implant-masking lithography steps compared to the conventional inversion mode or JLT technologies, respectively. For the n-FET mode with a film thickness of 5 nm and doping concentration of ${1} \times {10}^{{19}}$ /cm3, a threshold voltage of 0.42 V, a subthreshold swing of 172 mV/dec, an ON-current of $77.6~\mu \text{A}/\mu \text{m}$ , and an OFF-current of 100 fA/ $\mu \text{m}$ were obtained.