RESUMEN
We studied the metal gate work function of different metal electrode and high-k dielectric combinations by monitoring the flat band voltage shift with dielectric thicknesses using capacitance-voltage measurements. We investigated the impact of different thermal treatments on the work function and linked any shift in the work function, leading to an effective work function, to the dipole formation at the metal/high-k and/or high-k/SiO2 interface. We corroborated the findings with the erase performance of metal/high-k/ONO/Si (MHONOS) capacitors that are identical to the gate stack in three-dimensional (3D) NAND flash. We demonstrate that though the work function extraction is convoluted by the dipole formation, the erase performance is not significantly affected by it.
RESUMEN
AIM: Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and is one of the most common requests for electrodiagnosis. We aimed to note the relationship of subjective symptom severity of CTS, with objective electrophysiological severity and psychological status of patients. PATIENTS AND METHODS: One hundred and forty-four consecutive patients of CTS referred to neurophysiology laboratory of a tertiary care hospital over 1 year were prospectively studied. Boston CTS Assessment Questionnaire (BCTSAQ) and visual analog scale (VAS) were used to assess subjective symptom severity. Psychological status was assessed by Hospital Anxiety and Depression Scale (HADS). Electrophysiological severity of CTS was estimated by median motor distal latency and median to ulnar peak sensory latency difference across the wrist. Each parameter in both hands was scored from 0 to 3 depending on the severity grade, and a composite electrophysiological severity score (CEPSS) was calculated for each patient by summing up the scores in both hands. Statistical analysis was done by Spearman's rank correlation test. RESULTS: There was significant correlation of BCTSAQ with VAS (P = 0.001), HADS anxiety score (P < 0.001), and HADS depression score (P = 0.01). CEPSS had no significant correlation with VAS (P = 0.103), HADS anxiety score (P = 0.211), or HADS depression score (P = 0.55). CEPSS had a borderline correlation with BCTSAQ (P = 0.048). CONCLUSIONS: While the subjective symptoms of CTS are well correlated with psychological factors, their correlation with objective electrophysiological severity is weak. Hence, prompt treatment of psychological comorbidity is important in symptomatic management of CTS; decision about surgical intervention should be based on electrophysiological severity rather than symptom severity.
