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Detection of Collector Emitter Pipes in NPN Transistors

IP.com Disclosure Number: IPCOM000075506D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Bohg, A: AUTHOR [+2]

Abstract

Collector-emitter pipes in NPN transistors can be readily detected, without using external electrical connections. The transistors are tested rapidly and nondestructively.

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Detection of Collector Emitter Pipes in NPN Transistors

Collector-emitter pipes in NPN transistors can be readily detected, without using external electrical connections. The transistors are tested rapidly and nondestructively.

After the oxide has been removed from the surface, the semiconductor arrangement comprising NPN transistors is immersed for 5 seconds, while being exposed to a bright light source, in a solution of 0.2 g of CuSO(4), 10 ml of H(2)O, and 5 drops of HF.

Only little Cu is deposited on the N+ doped emitters which are electrically separated from the N-collector via the P-doped base. In comparison with this, an essentially greater quantity of Cu is deposited on the emitters which are electrically connected to the collector via a pipe extending through the base region. After evaluation of the testing process described, the Cu is removed by etching.

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