Hot-carrier induced drain leakage current in n-channel MOSFET

Hot-carrier induced drain leakage current in n-channel MOSFET´s has been found. Two leakage mechanisms exist at least. The leakage current for one mechanism can be characterized by it, exponential dependence on the drain voltage, approximate proportionality to the stress time, and very small (0.10eV) activation energy. The other mechanism can be characterized by its somewhat ohmic-like dependence on the drain voltage, approximate quadratic dependence on the stress time, and relatively large (0.29eV) activation energy. When stress is imposed by triode-mode operation, the former mechanism is dominant. For pentode-mode operation, the former is followed by the latter. The drain leakage current is observed for conventional, LDD and ALDD (Advanced LDD) structures, although they differ in magnitude. This hot-carrier induced drain leakage current may cause functional failure in DRAM cell or in resistor-load type SRAM cell, while the corresponding degradation in channel conductance may not.