On the non-Arrhenius behavior of negative-bias temperature instability

Evidence from negative-bias temperature stressing of the ultrathin Si3N4/SiOx gate p-channel field-effect transistor indicates that non-Arrhenius behavior is a consequence of the superposition of two distinct defect generation mechanisms with different power-law time dependence (t(n)) and activation energy (E-a). The two mechanisms are (1) a hole trapping mechanism (t(0.1); E-a similar to 0.02 eV) and (2) the classical hydrogen diffusion mechanism (t(0.25); E-a similar to 0.2-0.3 eV). When temperature increases, the latter gradually dominates, causing the exponent n, of the overall time-dependent shift of the device threshold voltage (parallel to Delta V-th parallel to(1+2)proportional to t(n)), to increase. Eliminating the contribution of the hole trapping mechanism, i.e. parallel to Delta V-th parallel to(1) from overall threshold voltage shift consistently reproduces parallel to Delta V-th parallel to(2)proportional to t(n) characteristics which bear the classical signature of negative-bias temperature instability, i.e., n approximate to 0.25 and is independent of temperature. (c) 2006 American Institute of Physics.