Generation of interface traps by internal photoemission of electrons from both the Al interface and the Si interface of an Alhyphen;SiO2hyphen;Si structure has been studied. The generation rate differs significantly between steam oxide and dry oxide samples, and among the dry oxide samples, the posthyphen;metalhyphen;anneal (PMA) treatment results in an appreciable reduction of this rate. A characteristic peak in the interface trap distribution, similar to the one generated by ionizing radiation, has been observed for all samples. For a given injection condition, the magnitude of this peak depends on the oxidation and PMA treatments, and is in the order (steam oxide)(dry oxide/no PMA)(dry oxide/PMA). For a given sample, the peak increases with the applied electric field and the total injected charge for either polarity. When the injection is made from the Si interface, the generation rate also depends on the energy of the incident photons, while no such dependence is observed for injection from the Al interface. A qualitative model is proposed to interpret the observations.
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