TANAKA Koichiro Kyusyu Institute of Technology, Center for Microelectronic Systems, Research Ass, マイクロ化総合技術センター, 助手 (40253570)
AOKI Satoshi Kyusyu Institute of Technology, Center for Microelectronic Systems, Research Ass, マイクロ化総合技術センター, 助手 (40231758)
Thin-film-transistor tenhnology has investigated from the view points of material preparation and device structures. Thin films of polycrystaline silicon and field effect transistors have been investigated.
・In order to enhance the signal processing speed of thin-film-transistor cricuits, it is desirable to design and fabricate each transistor in a circuit in a single polycrystalline grain. In order to realize this ideal situation, it is necessary to control the position of crystal and the growth speed of the crystal grains. We have found (1) enhancement of nucleation rate of amorphous silicon, and (2) reduction of the grain growth rate by irradiation of amorphous silicon with ions of innert species. Using these phenomena, we have demonstarated the control of crystallization sites of polycrystalline silicon films.
・Thin-films transistors fabricated on the polycrystalline silicon film prepared using the above nucleation-controlled method have been verified to show about 3 times higher operation speed than those fabricated using the conventional method.
・It has been demonstrated that, using the nucleation control method, thin-film transistors can be shrinked down to 0.6 mum and circuits composed of these transistors can operate. A test oscilation circuit has been designed and fabricated, which operated at the frequency range of several MHz at supply voltage of 5 V.
Application of field programmable analog and digital ICs to implementation of pulse signal processing circuits has been investigated.
・It has been found that analog/digital mixed signal circuits can be realized by converting analog signals to digitl signals in field progarammable analog arrays (FPAAs) and jointing with field programmable gate arrays (FPGAs).
・Using FPAA and FPGA,voltage controlled oscilator, ADC,DAC,and countors has been implemented and impletation method has been established.