Research On The Structural Improvement Of Metal Oxide Field Effect Transistors

With the rapid development of the display industry,the field effect transistors?FETs?have attracted much attention as one of the key components of flat panel display.At present,amorphous silicon?a-Si:H?FETs and low temperature poly-silicon?LTPS?FETs are usually used as switching devices for liquid crystal display?LCD?pixels.For the active-matrix organic light-emitting diode?AMOLED?of the next-generation display technology,each pixel needs two FETs,including one switching and one driving,which puts forward higher requirements on the performance of the FETs?carrier mobility is greater than 10 cm²/Vs?.Metal oxide FETs are being widely investigated due to their excellent electrical properties,large-area uniformity and low preparation temperature.In this dissertation,electrospinning and sol-gel methods were used to prepare high-performance metal oxide FETs.This dissertation is divided into three parts:Part one:The electrospun nanofibers were welded using an epoxy resin as an adhesive to improve the adhesion between the fibers and reduce the contact resistance.Based on the advantages of the welding procedure,the FETs based on the welded In₂O₃nanofibers were fabricated and exhibit superior electrical performance.Part two:Combining with the welding procedure,the proper dopant was selected to dope In₂O₃ nanofibers,and the device performance can be well regulated.When SiO₂was substituted by high-k ZrO_x as dielectric,the electrical performances of the electronic devices can be further improved.Meanwhile,the bias stability of the FETs is significantly enhanced by the proper dopants.Part three:The FETs with a bilayer structure without other dopants was designed.In this device,the channel layer was composed of the thin films with two layers of In₂O₃annealed at different temperatures.In₂O₃ thin film with higher annealing temperature provide high carrier concentration,which maximizes charge accumulation and leads to high mobility;In₂O₃ thin film with lower annealing temperature guarantees the low off-state current and suitable threshold voltage by adjusting the channel conductance.The results indicate that the electrical performance and bias stability of the bilayer device are much better than that of the single-layer In₂O₃ device.