Gate leakage current simulation for nanoscale NMOSFETs with nitrided gate dielectric by Boltzmann transport equation

We present an efficient but rigorous method to calculate gate leakage current for nanoscale devices, with and without nitrided gate dielectric. We achieve this by utilizing our results from the spherical harmonic Boltzmann transport equation calculations, which give the distribution function fairly fast. We calculate tunneling current using the WKB method and include potential barrier lowering due to image charge. We calculate gate currents for pure oxide gate dielectric, and for nitrided devices we use our modified model to calculate the same for different biases and gate lengths. As evident from our results, nitridation of gate dielectric leads to a reduction in gate leakage current by several orders of magnitude, albeit with about 20% reduction in mobility. Nitridation of gate dielectric has been an important tool in our quest for nanoscale devices. In this work we have proposed a physical model for nitrided gate devices that will go a long way in accurately predicting nanoscale device performances.