TCAD simulation of tunneling leakage current in CaF2/Si(111) MIS structures

• We model tunneling leakages through Au/CaF2/Si(111) structure using TCAD simulators.
• The main attention is paid to adaptation of professional simulators to the case of fluorite.
• A simplified model accounting for large transverse momentum is introduced.
• The experimental results are reasonably reproduced by the TCAD simulations.
• A possibility to simulate non-equilibrium tunneling through CaF2 is demonstrated.

We introduce a simulation technique suitable to model the tunneling leakage current in the metal(polySi)/CaF2/Si(111) MIS structures using TCAD simulators Minimos-NT and ViennaSHE. The simulations are performed using the real physical parameters of the CaF2/Si tunnel barrier. The results obtained for the case of near-equilibrium carrier transport are in a good agreement with experimental data and also with the simulation results yielded by our reference physical model. The obtained non-equilibrium hot-electron tunnel leakages in the hypothetical transistors with CaF2 as a gate dielectric are comparable to those in the structures with silicon dioxide. Being an important step forward for the device application of calcium fluorite, this work opens the possibility of simulating the characteristics of different silicon-based systems with crystalline insulators.