Detrapping phenomena in stressed MOS devices are observed by monitoring electrical characteristics after a constant current stress is applied. The “see-saw” behavior of the density of interface states and the subsequent partial recovery of the threshold voltage give evidence that detrapping occurs in the capacitor and transistor. Threshold voltage reversal has two components, thermal recovery (TR) and field-assisted-recovery (FAR). These results suggest the occurrence of a degradation reversal which could be of importance in future device design.

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s-D-4 99.41tm. The oxide thickness is 15nm and the gate electrode material is doped polysilicon. All transistors used are conventional single-drain devices. Constant-current stress (Fowler-Nordheim injection) at fixed temperature is used to ensurc that generated traps and trapped charges are uniformly distributed across the oxide cross-section, assuming edge effects can be neglected. In order to provide sufficient electrons for injection from p-type subsffate, the sample is continuously illuminated throughout current stressing. Voltage versus time measurements are performed on capacitors with a current density of 5x10-5 Ncmz until a voltage shift of about 200 mV is obtained. C-V measurements are taken prior to stress and at time intervals subsequent to stressing. C-V curves are analyzed to obtain the D11 versus energy plot.t6l For quasi-static measurements, ramp rates of 50 mV/s and 10mV/s are used. Transistors are stressed for 1000 seconds with a current density of 6x10-5 Ncmz. Poststress electrical characteristics are then monitored for up to lOa seconds. Vtrr is determined at IprlpA. Maximum 8m is calculated in the linear region with Vur 0.lV. The temperature dependence of the post-stress behavior is studied with threshold voltage and transconductance measurements between 81K and 373K.

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Electrical characterization of metal-insulator-semiconductor diodes fabricated from laser-ablated Yba 2 Cu 3 O 7−δ /yttria-stabilized zirconia films on Si substrates,"