The effect of source/drain (S/D) parasitic resistance has been experimentally investigated for amorphous silicon (a-Si:H) thin film transistors (TFTs). In general, the apparent field effect mobility decreases with decreasing channel length. However, the apparent threshold voltage is relatively constant. This may be attributed to an ohmic parasitic resistance due to the use of ion-implanted n+ S/D regions. Self-consistent results were obtained from both TFTs and from independent test structures for the TFT parasitic resistance, contact resistance, and sheet resistance. The results showed that the current spreading under the S/D regions is most critical in determining the magnitude of the total parasitic resistance. In this regard, both the S/D ion implantation and the S/D to gate overlap reduce the total parasitic resistance. Finally, the parasitic resistance is modeled as a gate voltage-modulated channel resistance, under the gate overlap, in series with a constant minimum contact resistance.
This paper describes and evaluates the incorporation of novel Stress Concentration Region (SCR) in silicon based cantilevers to enhance piezoresistive displacement, force, and torque sensitivities. In brief, SCR is a region, on the cantilever, with a thickness smaller than the cantilever thickness and of an appropriate length to localize stress where piezoresistors are implanted. It was found that in order to improve the sensitivity the length, thickness and placement of the SCR on the cantilever have to be optimized. Performing the optimization can result in a 2X, 5X and 3X improvement in the piezoresistive displacement, force and torque sensitivity, respectively. ANSYS, a well-known Finite Element Analysis (FEA) software, was used to analyze and optimize the above stated parameters of the SCR.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.