High Performance Fin-like Thin Film Transistors Based On In-plane Silicon Nanowires

In recent years,flat panel display(FPD)is closely bond to our daily life.With the rapid development,it has been applied to and dominated all kind of fileds,such as entertainment,medicine,transportation and industry.Thin film Transistor Liquid Crystal Display(TFT-LCD)has played an important role in FPD and been widely paid attention to.Industry now substitudes amorphors silicon(a-Si:H)with Low-temperature poly-crystalline silicon(LTPS)or InGaZnO,for its relatively low motilities.Even though their cons,pros matter much more,since IGZO still suffers low mobilities for high-resolution FPD and LTPS undergoes high thermal budgets and unevenness.Therefore,more and more nanomaterials have been tried to solve the problems.Even though their attractive performance,the issue of scaling and position have not been coped with yet,thus blocking their way towards industrialization.In this Thesis,we will employ the "in-plane solid-liquid-solid"(IPSLS)silicon nanowire,along with its good properties and compatibility with microelectronics industry,to address the issue.Based on free-growth dynamics and guided-growth mechanism,we develop a "nano-droplet scanning" methodology for silicon nanowires array.The array can then be fabricated into large-scale,high performance and transparent TFT.Further,we modified the guided-growth model and develop a "one nanowire multi-electrical-channels"methodology to fabricate better TFT.All these shed lights on the road towards the industrialization and commercialization of SiNWs TFT.As such,the major results and innovative contributions of this Thesis are listed as follows:1)Based on free-growth dynamics and guided-growth mechanism,we for the first time archive a high yield(more than 98%)of nanowire array along the straight guiding edges.We find a strict relationship among the diameter of the nanowire,the indium droplet and the height of indium film,and design a better scheme for optimizing guided growth.Along with the most suitable diameter of the indium droplets at certain height of the edge,we modify the original straight guiding model and set up new one for the situation of curve guiding.Meanwhile,the problem of diameter mismatch,deviation,collision,etc.In this case,we develop a methodology to grow nanowire along guiding edges with any shape and archive a high yield.2)We develop a "nano-droplet-scanning" methodology to fabricate large-scale in-plane SiNWs TFT.The SiNWs array are fabricated upon 2-inch glass,and the TFT has a hole nobilities over 100cm2 V-1 s-1 and a subthreshold under 163 mV/dec.Specifically,due to the alignments of SiNW array and selective etching of remnant a-Si:H film,the SiNW TFT is almost transparent to light.To point out,the key parameters of SiNWs are much better than a-Si:H,IGZO,and the thermal budget is much lower than LTPS and other nanomaterials,which indicate a new poly-Si TFT technology standard for high performance transparent macro electronics and high definition displays.3)We develop a "one nanowire multi-electrical-channel" TFT according to the curve guiding model.We archive a high-performance fin-FET with a hole motilities over 200 cm 2 V-1s-1and a subthreshold under 121 mV/dec.Comparing to SiNWs array,multichannel nanowire TFT are far more cost-effective with more uniform electrical channel.Most importantly it has twice as many mobility as SiNWs array.In this way,Multichannel SiNW TFT indicates a new a-Si TFT technology standard for high performance transparent microelectronics and high definition displays.