Behavior of subthreshold conduction in junctionless transistors

• The subthreshold conduction on junctionless transistors (JLTs) has been investigated.
• JLTs have reduced portion of diffusion current in subthreshold conduction.
• The effective barrier of JLT in subthreshold conduction is suppressed.
• However, degradation of effective barrier in short channel JLT wasn’t severe.
• Observed subthreshold conduction behaviors lead to high DIBL in JLTs.

In this work, the effect of high channel doping concentration and unique structure of junctionless transistors (JLTs) is investigated in the subthreshold conduction regime. Both experimental results and simulation work show that JLTs have reduced portion of the diffusion conduction and lower effective barrier height between source/drain and the silicon channel in subthreshold regime, compared to conventional inversion-mode (IM) transistors. Finally, it leads to a relatively large DIBL value in JLTs, owing to degraded gate controllability on channel region and strong drain bias effect. However, JLTs showed a better immunity against short channel effect in terms of degradation of the effective barrier height value.