Metastability mechanisms in thin film transistors quantitatively resolved using post-stress relaxation of threshold voltage

A new approach is presented to resolve bias-induced metastability mechanisms in hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs). The post stress relaxation of threshold voltage (V(T)) was employed to quantitatively distinguish between the charge trapping process in gate dielectric and defect state creation in active layer of transistor. The kinetics of the charge de-trapping from the SiN traps is analytically modeled and a Gaussian distribution of gap states is extracted for the SiN. Indeed, the relaxation in V(T) is in good agreement with the theory underlying the kinetics of charge de-trapping from gate dielectric. For the TFTs used in this work, the charge trapping in the SiN gate dielectric is shown to be the dominant metastability mechanism even at bias stress levels as low as 10 V

Effect of gate dielectric scaling in nanometer scale vertical thin film transistors

A short channel vertical thin film transistor (VTFT) with 30 nm SiN x gate dielectric is reported for low voltage, high-resolution active matrix applications. The device demonstrates an ON/OFF current ratio as high as 109, leakage current in the fA range, and a sub-threshold slope steeper than 0.23 V/dec exhibiting a marked improvement with scaling of the gate dielectric thickness. © 2011 American Institute of Physics

Case series supporting heme detoxification via therapeutic plasma exchange in acute multiorgan failure syndrome resistant to red blood cell exchange in sickle cell disease

© 2017 AABB BACKGROUND: Depletion of haptoglobin (Hp) and hemopexin (Hx) with increase in free hemoglobin and heme are important etiologies of vaso-occlusive complications in sickle cell disease (SCD). This study is the first to show an association between clinical improvement in SCD and repletion of Hp and Hx by therapeutic plasma exchange (TPE) using plasma replacement. STUDY DESIGN AND METHODS: Thirteen fresh-frozen plasma (FFP) units derived from consecutive whole blood donations were thawed at 37°C after 10 months of storage; Hp and Hx concentrations immediately postthaw and after 5 days of refrigerated storage were analyzed by enzyme-linked immunosorbent assay (ELISA). All SCD patients presenting to a single institution over a 2-year period with acute multiorgan failure syndrome resistant to red blood cell exchange (RCE) were treated with TPE with FFP replacement; concentrations of Hp, Hx, and heme were evaluated before and after TPE by ELISA. RESULTS: Plasma concentrations of Hp and Hx decreased approximately 20% (p ≤ 0.002) after 5 days of refrigerated storage. Significant mean fold increases after TPE of 10 for Hp (p \u3c 0.005) and seven for Hx (p \u3c 0.003) and a 30% mean decrease in heme concentrations (p = 0.07) were noted in association with clinical improvement (three patients), whereas minimal increases in Hp and Hx were associated with continued clinical deterioration in one patient. CONCLUSION: Fresh-frozen plasma rather than thawed plasma is optimal for Hp and Hx replacement. Patient data are consistent with Hp and Hx increases via TPE limiting clinical toxicity of worsened hemolysis associated with severe vaso-occlusive complications refractory to RCE in SCD