Semiconductor device lifetime estimation method and reliability simulation method

摘要

A hot carrier lifetime of a MOS transistor is estimated, depending on model formulas: 1/tau=1/tauSUB0/SUB+1/tauSUBb/SUB; tauSUBb/SUB∝1SUBsub/SUBSUP-mb/SUP.ISUBd/SUBSUPmb-2/SUP.exp(a/|VSUBbs/SUB|), where tau denotes a lifetime, ISUBsub /SUBdenotes a substrate current, ISUBd /SUBdenotes a drain current, VSUBbs /SUBdenotes a substrate voltage, tauSUB0 /SUBdenotes a lifetime at the time the substrate voltage VSUBbs/SUB=0, tauSUBb /SUBdenotes a quantity representing deterioration of a lifetime at the time the substrate voltage |VSUBbs/SUB|0, and mb and 'a' are model parameters. Furthermore, a parameter Age representing a cumulative stress quantity is calculated depending on model formulas: Age=AgeSUB0/SUB+AgeSUBb/SUB; AgeSUBb/SUB=∫1/HSUBb/SUB[ISUBsub/SUBSUPmb/SUP.ISUBd/SUBSUP2-m/SUP].exp(-a/|VSUBbs/SUB|)dt, where t denotes time, HSUBb /SUBis a model parameter, AgeSUB0 /SUBdenotes a parameter representing a cumulative stress quantity at the time the substrate voltage VSUBbs/SUB=0, and AgeSUBbs /SUBdenotes a quantity representing an increase of the cumulative stress quantity at the time the substrate voltage at |VSUBbs/SUB|0. Thereby, a lifetime in actual use is determined with accuracy even when a substrate voltage is applied, and circuit characteristic degradation is simulated with high accuracy.