HIGH FREQUENCY TUNNEL DEVICE STUDY
RAYTHEON CO WALTHAM MA
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Research was continued on low-noise microwave amplification by tunneling. An all-solid-state device and a thin-film cathode in conjunction with a microwave structure were studied. Metal base transistor structures were fabricated with Ge collectors, thin-film Au bases and single crystal Ge, Si, and evaporated CdS emitters. Plasma oxidation of Al films deposited upon Ge was performed. Metal-interface amplifier structures with evaporated CdS emitters have shown no improvement and still suggest that hot electrons are not involved in the current transfer mechanism. Approximately 150 test cathode structures were produced. Pulsed emission current densities of up to several amperes per sq cm. were obtained. The requirements on cathode dimensions and performance necessary to achieve 20 db gain at 10 kmc were theoretically established. Since the tunneling insulator appears to be one of the very critical elements in the production of a suitable tunnel cathode, a study of these layers was undertaken. From the results of experimental measures, attempts were made to determine whether the Al-Al2O3-Au structure previously described is an advantageous one, and which basic factors are responsible for limiting the performance. A theoretical model is postulated to explain the functioning of this structure.
- Electrical and Electronic Equipment