Accession Number : AD0821392

Title :   RELIABILITY PHYSICS STUDIES ON TRANSISTORS.

Descriptive Note : Final rept. for period ending 20 Mar 67,

Corporate Author : ITT SEMICONDUCTOR PRODUCTS LABS PALO ALTO CA

Personal Author(s) : Scarlett, R. M. ; Riddle, Grant C.

Report Date : SEP 1967

Pagination or Media Count : 104

Abstract : Section 1 deals with the general theory of lateral instability and electrical test methods for detecting it. A general model is set up, from which the criterion for stability can be determined under various conditions. It is shown that at high collector voltage an electrical instability exists which is much faster than the thermal instability occurring at lower voltages. Emitter resistance can be effective in stabilizing against both types of instability provided the emitter is divided into small enough domains, each with an independent resistance. These domains may be as small as 5 u in lateral dimension. A new and convenient electrical test for determining the onset of instability is described. A comparison of this test with previously used pulse tests shows that the 'stability index' pulse test is the most conservative in predicting the onset of the hot spot formation which precedes second breakdown. An experimental study of second breakdown at high collector voltage supports the electrical instability model. Section 2 describes work done to find a material suitable for a distributed emitter resistor. Both evaporated mixtures and reactions induced by heating suitable combinations of materials on the chip were considered. In the former category, chromium-germanium and aluminum-aluminum oxide co-evaporated mixtures produced stable films up to about 1/100 ohm cm. The required 1 - 10 ohm-cm could not be obtained stably. In the latter category, resistive material produced by reacting Al with SiO2 and by oxidizing nickel films were investigated. Neither of these proved satisfactory.

Descriptors :   (*TRANSISTORS, RELIABILITY), FAILURE(MECHANICS), STABILITY, ELECTRICAL RESISTANCE, SEMICONDUCTORS, VOLTAGE, ALUMINUM, SILICON, DIOXIDES, NICKEL ALLOYS, OXIDES, TEST METHODS.

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE