Investigation of NBTI Effect in P-Type Junctionless Transistor with Uniform and Graded Doping Profiles

This paper presents the reliability effect analysis of Negative Bias Temperature Instability (NBTI) in p-type junctionless transistor (JLT) under uniform and non-uniform doping profiles using Global TCAD Solution. The work compares the change in threshold voltage ( Δ Vth ) with the stress time and relaxation time for uniform and non-uniform doping profile in long and short channel p-type JLT. When negative Vgs and Vds are applied in the device, large number of interface traps are generated due to the dissociation of Si–H bonds along with the silicon-oxide interface. This results in the subsequent increase in the threshold voltage (Vth), thereby decreasing the driving capability and hence affects the device performance. Further, it is observed, increase in temperature causes more increase in the threshold voltage (Vth). This effect is due to breaking of more Si–H bonds, generating more interface traps. Simulation results after comparison shows that this change in Δ Vth under stress is more in non-uniform than in uniform p-type JLT, this is due to the fact that an increase of trap charges on uniform p-type JLT is less compared to non-uniform p-type JLT. It is also observed that short-channel devices are more prone to NBTI effect.