Effect of P-SiN Passivation Layer on Time-Dependent Dielectric Breakdown in SiO2

Abstract

Effects of hydrogen and mechanical stress due to a plasma deposited SiN passivation layer on time-dependent dielectric breakdown were investigated, and it is found that the p-SiN layer degrades the TDDB characteristics concerned with interface state and trap generation. The native trap density remarkably increases with annealing MOS capacitors encapsulated by p-SiN layer. The degradation of interface state, which is induced by the electron injections, is enhanced on the devices with p-SiN layer by annealing. These degradations are mainly caused by the diffusion of atomic hydrogen to the SiO2-Si interface. The atomic hydrogen is considered to be released from the N-H bond in p-SiN layer by annealing. Large mechanical stress, up to 5~8 × 109 dyne/cm2, due to p-SiN layer also introduces the degradation of TDDB characteristics in a random failure region.