Enhancement Mode Transferred-Electron Logic Devices (TELDs).

摘要

This report describes the results of the quasi-enhancement mode transferred-electron logic program which was intended to develop GaAs devices suitable for this mode of operation and evaluate them in pulse amplifier circuits. Epitaxial GaAs wafers were grown by vapor hydride synthesis. Electrolytic etching of the wafers was used to obtain uniform nd product across the wafers. Quasi-enhancement mode devices were fabricated and dc, rf, and switching parameters were characterized. Current drop of the order of 10-15% was measured. Trigger sensitivity of these devices was 1.5-2.5 V. The quality of the epi-layer substrate has to be further improved so that lower nd product can be used; this will improve the trigger sensitivity and reduce device dissipation. A TELD-FET circuit evaluated as a pulse amplifier was found to provide voltage gain with good trigger sensitivity and high-frequency response. This configuration combines the advantages of FETs (good trigger sensitivity) and TELDs (threshold and neuristor) and is potentially very useful for ultrahigh-speed logic. Voltage gains of up to 4 were realized for about 100-ps pulse width (half-height) operation. (Author)