Temperature Modeling Of Total Ionizing Dose Effect In Deep Sub-micron CMOS

With the development of aviation technology, researchers pay more and moreattention on semiconductor devices and circuits which suffer from total ionizingdose(TID).As an important unit of integral circuits, CMOS devices which could sufferdegradation under the stress of TID, may lead integral circuit or chips break down.This article discusses the temperature effect on TID by giving a deep submicronCMOS model under TID stress and shows the verification results.Firstly, considering the calculation efficiency of the implicit surface potentialfunction and the limitation at s=0, the potential function is modified and simplified.Then the new potential function is proved to describe the device character well beforeirradiation and a TID model based on this new potential function is built up.Secondly, because the gate oxide of deep submicron CMOS device is ultra thin,oxide traps and interface traps both could be ignored. However, these two carries inshallow trench isolation(STI) region become more and more important in discussingthe degradation of the device. A potential component radis introduced to describethese two carries in the surface potential function and along with the new drainfunction to describe the transfer character of CMOS device.At last, start from the continuity function, we derivate the original functions ofoxide traps and interface traps under TID stress. Then, the original functions aremodified with temperature dependency and leakage current character along withtemperature is verified. According to the theory and experiment, electronic field, totaldose, oxide thickness and temperature are related to the degradation character ofsemiconductor device. Refer to NMOS device，when it suffers the same amount oftotal dose, as the temperature is increasing, the oxide traps decrease and the interfacetraps increase, leading to the decrease of the leakage current.