Polycrystalline silicon （poly-Si） thin film has been prepared by means of nickel-disilicide （NiSi2） assisted excimer laser crystallization （ELC）. The process to prepare a sample includes two steps. One step cons...Polycrystalline silicon （poly-Si） thin film has been prepared by means of nickel-disilicide （NiSi2） assisted excimer laser crystallization （ELC）. The process to prepare a sample includes two steps. One step consists of the formation of NiSi2 precipitates by heat-treating the dehydrogenated amorphous silicon （a-Si） coated with a thin layer of Ni. And the other step consists of the formation of poly-Si grains by means of ELC. According to the test results of scanning electron microscopy （SEM）, another grain growth model named two-interface grain growth has been proposed to contrast with the conventional Ni-metal-induced lateral crystallization （Ni-MILC） model and the ELC model. That is, an additional grain growth interface other than that in conventional ELC is formed, which consists of NiSi2 precipitates and a-Si. The processes for grain growth according to various excimer laser energy densities delivered to the a-Si film have been discussed. It is discovered that grains with needle shape and most of a uniform orientation are formed which grow up with NiSi2 precipitates as seeds. The reason for the formation of such grains which are different from that of Ni-MILC without migration of Ni atoms is not clear. Our model and analysis point out a method to prepare grains with needle shape and mostly of a uniform orientation. If such grains are utilized to make thin-film transistor, its characteristics may be improved.展开更多
This paper reports on a successful demonstration of poly-Si TFT nonvolatile memory with a much reduced thermal-budget.The TFT uses uniform Si quantum-dots（size -10 nm and density -10-（11） cm-（-2）） as storage med...This paper reports on a successful demonstration of poly-Si TFT nonvolatile memory with a much reduced thermal-budget.The TFT uses uniform Si quantum-dots（size -10 nm and density -10-（11） cm-（-2）） as storage media,obtained via LPCVD by flashing SiH4/H2 at 580℃for 15 s on a Si3N4 surface.The poly-Si grain-enlargement step was shifted after source/drain formation.The NiSix-silicided source/drain enables a fast lateral-recrystallization,and thus grain-enlargement can be accomplished by a much reduced thermal-cycle（i.e., 550℃/4 h）.The excellent memory characteristics suggest that the proposed poly-Si TFT Si quantum-dot memory and associated processes are promising for use in wider TFT applications,such as system-on-glass.展开更多
基金Project supported by the National High Technology Development Program of China （Grant No 2002AA303250） and by the National Natural Science Foundation of China （Grant No 60576056）.
文摘Polycrystalline silicon （poly-Si） thin film has been prepared by means of nickel-disilicide （NiSi2） assisted excimer laser crystallization （ELC）. The process to prepare a sample includes two steps. One step consists of the formation of NiSi2 precipitates by heat-treating the dehydrogenated amorphous silicon （a-Si） coated with a thin layer of Ni. And the other step consists of the formation of poly-Si grains by means of ELC. According to the test results of scanning electron microscopy （SEM）, another grain growth model named two-interface grain growth has been proposed to contrast with the conventional Ni-metal-induced lateral crystallization （Ni-MILC） model and the ELC model. That is, an additional grain growth interface other than that in conventional ELC is formed, which consists of NiSi2 precipitates and a-Si. The processes for grain growth according to various excimer laser energy densities delivered to the a-Si film have been discussed. It is discovered that grains with needle shape and most of a uniform orientation are formed which grow up with NiSi2 precipitates as seeds. The reason for the formation of such grains which are different from that of Ni-MILC without migration of Ni atoms is not clear. Our model and analysis point out a method to prepare grains with needle shape and mostly of a uniform orientation. If such grains are utilized to make thin-film transistor, its characteristics may be improved.
文摘This paper reports on a successful demonstration of poly-Si TFT nonvolatile memory with a much reduced thermal-budget.The TFT uses uniform Si quantum-dots（size -10 nm and density -10-（11） cm-（-2）） as storage media,obtained via LPCVD by flashing SiH4/H2 at 580℃for 15 s on a Si3N4 surface.The poly-Si grain-enlargement step was shifted after source/drain formation.The NiSix-silicided source/drain enables a fast lateral-recrystallization,and thus grain-enlargement can be accomplished by a much reduced thermal-cycle（i.e., 550℃/4 h）.The excellent memory characteristics suggest that the proposed poly-Si TFT Si quantum-dot memory and associated processes are promising for use in wider TFT applications,such as system-on-glass.
