Study of p-n Junction Tunnel Emitter for Vacuum Integrated Circuits.

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The tunnel emitter is expected to have very promising characteristics as a cathode of vacuum tubes ; because its higher emission density, lower noise temperature, higher reliability and so on, compared with those of usual thermal cathods. In this research, we have tried to fabricate p-n and MIS type micron size tunnel emitter array on Si substrate for the application to vacuum microelectronic tube. Design, fabrication and characterization of the tunnel emitter array were performed. The results were as follows ;(1) Semiconductor film deposition on Si substrate for p-n junction tunnel emitterSemiconductor (Ge) films were deposited by DC bias sputtering system. The electrical properties of the films were investigated as a function of target voltage and sputtering gas pressure. Film properties were improved with increasing ratio of Ar gas pressure to target voltage. From these results, it is considered that by increasing the Ar gas pressure to target voltage ratio i, e. decrease of sputter … More ing energy, the defects which are due to the hish energy particles from the target are decreased and the electrical properties of the films are improved. By using this system at low energy sputtering conditions, Ge films were deposited on Si (100) substrates. The RHEED patterns showed that the films were not single crystal but polycrystal.(2) Design and fabrication of MIS tunnel emitter arrayTunnel current distribution of a emitter element was calculated as a function of element size. From the results of calculation, maximum element size was decided. Experimental arrays including 10 X 10 elements (60mum dia. each) on Si (100) substrate have been prepared by using conventional photo-lithography. Electrical characteristics of the array were measured and the results were systematically related to the fabrication conditions.(3) Vacuum system for tunnel emission measurementVacuum system for the measurement of tunnel emission current and electron energy distribution was fabricated with a turbo molecular pump and a stainless steel chamber. The background pressure of this system was <1 10^<-5>Pa. Less