igure 43. Trapping at interface: V ot and the voltage at mid-oxide when the gate bias is EGS1-0.2 MV/sm** su seconder SYots reversed kilorad(SiO2). Dose (kilorad(SiO2) Pt (charges/cm³ 3 [x1016] III-59 E (kV/cm) [x105] oxide thickness (A) silicon (kilorad(SiO2)) oxide thickness (A) Figure 44. Trapping at interface: trapped charge silicon (kilorad(SiO2)) distribution across the oxide when the gate bias is reversed at 2.5 kilorad(SiO2). Figure 45. Trapping at interface: electric field distribution across the oxide when the gate bias is reversed at 2.5 kilorad(SiO2). In a second set of calculations, we consider the case of interface plus bulk trapping. Z:WTRAPPOXDATWJLLISYST49Pois46pe.TXT-YY-18-Feb-1999 20:19:49 V ot (Volts) Voltage at mid-oxide (Volts) Figure 46. Trapping at interface plus oxide bulk: V ot and the voltage at mid-oxide when the gate bias is reversed at 2.5 kilorad(SiO2). VGS1=5Volts, EGS1=0.2 MV/cm**** temps en secondes ***VGS2=-5Volts, EGS2=-0.2 MV/cm Dose (kilorad(SiO2) No recovery is observed because, whereas the charge trapped near silicon decreases, the charge trapped in the half-region near gate increases. In this case, it is sufficient to make the charge increase. III-60 Pt (charges/cm³ [x1016] E (kV/cm) [x105] 1 10" oxide thickness (A) silicon (kilorad(SiO2)) oxide thickness (A) silicon Figure 47. Trapping at interface plus oxide bulk: (kilorad(SiO2)) trapped charge distribution across the oxide when the gate bias is reversed at Figure 48. Trapping at interface plus oxide bulk: 2.5 kilorad(SiO2) electric field distribution across the oxide when the gate bias is reversed at 2.5 kilorad(SiO2) In these figures, one can see the internal field modification across the oxide. At the end of the irradiation (50 kilorad), one can easily see the field collapse (FC) near silicon (positive electrode) and the field enhancement (FE) near the gate (negative electrode). As the field increases from 167 kV/cm before irradiation to nearly 300 kV/cm at 50 kilorad (Field-Enhancement), this has great importance in 