The Characteristics of New n-Type Polycrystalline Silicon Thin-Film Transistors Employing Alternating Magnetic-Field-Enhanced Rapid Thermal Annealing
We fabricated a new top-gate n-type depletion-mode polycrystalline silicon (poly-Si) thin-film transistor (TFT) employing alternating magnetic-field-enhanced rapid thermal annealing. An n+ amorphous silicon (n+ a-Si) layer was deposited to improve the contact resistance between the active Si and source/drain (S/D) metal. The proposed process was almost compatible with the widely used hydrogenated amorphous silicon (a-Si:H) TFT fabrication process. This new process offers better uniformity when compared to the conventional laser-crystallized poly-Si TFT process, because it involves nonlaser crystallization. The poly-Si TFT exhibited a threshold voltage (VTH) of -7.99 V at a drain bias of 0.1 V, a field-effect mobility of 7.14 cm2/V ldr s, a subthreshold swing (S) of 0.68 V/dec, and an ON/OFF current ratio of 107. The diffused phosphorous ions (P+ ions) in the channel reduced the VTH and increased the S value.
Metal-induced crystallization of amorphous silicon
The present invention provides an amorphous metal induced crystallization method. Amorphous silicon as a starting material, prepared through the corresponding pattern on the amorphous silicon LTO photolithography. Wherein the large area is referred to as positioning holes, a smaller area is referred to as a nickel source supplementary hole. Trace amount of nickel is then deposited, polysilicon induce large grains. In particular, a metal is introduced into the selected position of an amorphous material, a concentration slightly higher than the minimum concentration induced crystallization begins to occur, the metal is introduced in other positions, but its concentration is lower than the concentration of inducing crystallization occurs, may ensure crystallization rate and the crystallization-inducing metal mass provided. After setting the above metal element is introduced on the amorphous thin film thermally annealed. The results will form a large grain size polycrystalline silicon thin film according to the design arrangement. It can be prepared by the method of high uniformity, good quality polycrystalline silicon thin film, and process repeatability.
A model for predicting heat transfer through gypsum‐board/wood‐stud walls exposed to fire
To facilitate the development of cost-effective and flexible design options there is a need to develop models to predict the fire resistance of wood-frame building assemblies. Such assemblies often derive much of their fire resistance from a protective membrane composed of gypsum board. A simple two-dimensional computer model is presented to predict heat transfer through gypsum-board/wood-stud walls exposed to fire. Input data for the thermophysical properties of gypsum board were measured exploying standard bench-scale tests. Input data for wood were selected from the literature. Small-and full-scale fire resistance tests were conducted on gypsum-board/wood-stud wall assemblies to provide data for the validation of the model. The model is shown to predict heat transfer through these walls rather well.