Roughness-enhanced reliability of MOS tunneling diodes

Both electrical and optical reliabilities of PMOS and NMOS tunneling diodes are enhanced by oxide roughness, prepared by very high vacuum prebake technology. For rough PMOS devices, as compared to flat PMOS devices, the Weibull plot of T/sub BD/ shows a 2.5-fold enhancement at 63% failure rate, while both the D/sub 2/ and H/sub 2/-treated flat PMOS devices show similar inferior reliability. For rough NMOS devices, as compared to flat NMOS devices, the Weibull plot of T/sub BD/ shows a 4.9-fold enhancement at 63% failure rate. The time evolutions of the light emission from rough PMOS and NMOS diodes degrade much less than those of flat PMOS and NMOS diodes. The momentum reduction perpendicular to the Si/SiO/sub 2/ interface by roughness scattering could possibly make it difficult to form defects in the bulk oxide and at the Si/SiO/sub 2/ interface by the impact of the energetic electrons and holes.