| 摘要 |
<p>803,298. Semi-conductor devices. WESTERN ELECTRIC CO., Inc. June 5, 1956 [June 8, 1955], No. 17339/56. Class 37. A germanium PN junction device is stabilized against changes in the conductivity type of its exposed P-type surfaces by mounting in a sealed housing filled with oxygen. In one embodiment a grown NPN germanium bar 17 in which the P-type zone is thin is mounted between electrodes 16 which are sealed through a flanged metal sleeve 13. The germanium is then cleaned by etching in a mixture of 25 parts nitric and 3 parts hydrochloric acid, washed first in deionized water and then in ethyl alcohol and afterwards blown dry with nitrogen. The mounted bar is then stored in dry nitrogen until it can be encapsulated by welding a cover 11 to the flange of sleeve 13. The housing thus formed is then evacuated, refilled with oxygen and sealed by pinching off and welding the tubulation 12. An alloy type PNP transistor comprising indium or gallium emitter and collector electrode blobs fused to opposite faces of an N-type germanium wafer to one of which a ring base electrode is attached may also be stabilized by mounting in oxygen. The oxygen prevents the surface of the P-type germanium from being converted to N-type and thus shortcircuiting the junctions. The invention is applicable only where the surface current paths in the P-type material are small compared with similar paths in the N-type material since the oxygen tends to convert the N-type surfaces to P-type. Specification 760,563 is referred to.</p> |
