TINY MICROWAVE DEVICES

CD 1967077 E&MP123.001

Semiconductors

January 19, 1967

Granules of ordinary superfine sugar appear large alongside experimental semiconductor devices under development at Bell Telephone Laboratories.

The tiny devices, bulk-effect oscillators made from gallium arsenide, are being studied as sources of microwave and millimeter power for communications systems.

Solid-state devices such as these may someday replace medium-power vacuum tubes as microwave oscillators in many applications.

They are inherently compact and reliable, and do not require thermeonic cathodes. They generate microwaves directly when dc voltage is applied to them.

Vacuum tubes, on the other hand, depend on emission of electrons from a cathode, which eventually deteriorates, and require a source of cathode current and high-voltage power supply which tends to be bulky and expensive.

Although these gallium arsenide devices can barely be seen with the naked eye, the volume of semiconductor material they use in generating microwave energy is tens of times greater than in transistors and tunnel diodes operating at the same frequency.

As a consequence, they show promise of operating at higher voltages and thus higher power levels. 

Original Caption by Science Service
^©Bell Telephone Laboratories