AbstractA ternary compound results from the fast radiative processing of Ni/Ti bilayers on Si<100> substrates. In the Ti-Ni-Si system, Ni is the dominant moving specie at low temperatures while Si starts to diffuse at 575°C. For bilayers with Ti in excess, the final product,above 750°C, is a mixture of ternary compound and TiSi2 whereas excess Ni leads to a layer of NiSi between the substrate and the ternary layer, at tempera-tures below 700° C.
AbstractThe effect of rapid thermal annealing on the crystallization of arsenic and boron implanted amorphous silicon films is studied. Amorphous Si films of 4000 Å were deposited using LPCVD and implanted with arsenic or boron to doses of 5 × 1013, 5 × 1014, and 5 × 1015 cm−2. These films were then annealed using an Eaton Nova-400 RTA system (with temperature ranging from 900 to 1200 °C and dwell time ranging from 1 to 30 sec). The annealed films were studied using transmission electron microscopy, Hall effect measurement and temperature coefficient of resistance measurement. The optimal annealing conditions for the films were found.
ABSTRACTHydrogenated amorphous silicon (a-Si:H) films which were deposited by plasma enhanced chemical vapor deposition (PECVD) have been recrystallized by the two-step rapid thermal annealing (RTA) employing the halogen lamp. The a-Si:H films evolve hydrogen explosively during the high temperature crystallization step. In result, the recrystallized polycrystalline silicon (poly-Si) films have poor surface morphology. In order to avoid the hydrogen evolution, the films have undergone the dehydrogenation step prior to the crystallization step.Before the RTA process, the active area of thin film transistors (TFT's) was patterned. The prepatterning of the a-Si:H active islands may reduce the thermal damage to the glass substrate during the recrystallization. The computer generated simulation shows the heat propagation from the a-Si:H islands into the glass substrate. We have fabricated the poly-Si TFT's on silicon wafers. The maximum ON/OFF current ratio of the devices was over 10.
AbstractNickel Induced Lateral Crystallization (NILC) and Pulsed Rapid Thermal Annealing (PRTA) have been used to study new low temperature and high quality poly-silicon (poly-Si) films and thin film transistors (TFTs). The growth rate of poly-Si films has been found to greatly increase from 0.025μm/minute to 1.07μm/minute, and the drain current and performance of TFTs have increased by around 75%. The new poly-Si technology has good potential to apply in high performance, large area, fast throughput, low cost and even low temperature device applications.
AbstractLateral non-uniformities can be expected in the dopant diffusion front in the substrate in polysilicon-on-single crystal Si systems upon Rapid Thermal Annealing (RTA), because the grain boundaries in polysilicon act as fast diffusant pipelines and also possibly inject defects into the substrate, which can locally enhance diffusivities in the substrate due to dopant-point defect interactions. The lateral uniformity of As, B and P ultra-shallow junctions formed in the substrate by indiffusion from as-deposited amorphous or polysilicon films has been studied using concentration dependent etching and transmission electron microscopy. Due to a larger final grain size after annealing in the case of as-deposited amorphous Si films compared to asdeposited polysilicon films, there is significant lateral doping inhomogeneities in the diffusion front. However, the doping inhomogeneities are gradually smeared out as the impurities diffuse deeper into the substrate due to lateral as well as vertical diffusion.
Fabrication of Polycrystalline Si Films by Silicide-Enhanced Rapid Thermal Annealing and Their Application to Thin Film Transistors