Mechanism of hot-electron-induced nMOSFET´s degradation

Hot-carrier-induced MOSFET´s degradation has been thought to be due to carrier trapping in the gate oxide and/or interface-trap generation[1]-[3], The degradation Is caused by the injection of hot carriers Into the oxide above the channel outside the drain layer (Region A as shown in Ftg.1). Thus, in order to clarify the processes involved in degradation, It is important to know which carrier types are injected into Region A. Recently, a new experimental method has been proposed to determine the oxide portion into which hot carriers are injected[4]. Using this method, the dependence of bias conditions on hot carrier types injected into Region A can be determined[3][5]. This paper proposes a new experimental method using Intentional hot-electron (HE) and/or hot-hole (HH) injections into Region A to distinguish the trapped-electron effect from the generated interface-trap effect in HE-induced nMOSFET´s degradation, and analyze the causes of HE-induced transconductance degradation. Moreover, the critical hot electron energy for interface-trap generation is determined.