CdTe of well-defined composition has been deposited cathodically from an aqueous solution of CdSO4 and TeO2. Films with a rest potential of < --0.3V vs. SCE are n-type, those with a rest potential > --0.3V vs. SCE are p-type semiconductors. The rate of deposition increases with stirring rate; it is proportional to the TeO2 concentration but independent of the CdSO4 concentration. Films deposited at room temperature are amorphous, those deposited at higher temperatures are partly crystalline, the degree of crystallinity increasing with deposition temperature. Grain sizes are in the range 500-1000A. Annealing at 350~ causes the crystallite size to increase to ~0.5 #m.

In order to realize the large growth potentials of commercial wireless market segments such as local multi-point distribution services (LMDS) and point-topoint radio, system manufacturers will have to produce affordably-priced equipment for the consumer. One key issue is reducing the cost of packaging monolithic microwave integrated circuits (MMICs) for these applications, which operate in the frequency range of 18 to 40 GHz. This paper explores the applicability of ball-grid array (BGA) technology as an economical solution to microwave and millimeter-wave MMIC packaging.

The blackening of indium-tin oxide and tin oxide thin film substrates during rf sputter deposition of yttrium oxide has been investigated to determine the precise conditions and mechanisms effecting this phenomenon. It was determined that at argon pressures below 4 microns and/or with the substrate films grounded, the yttria films deposited were oxygen deficient. The subsequent reduction of the substrate film by the more stable yttria resulted in the blackened appearance of the film. The problem was further compounded when these electrically conductive substrates were of optimum properties (sheet resistance below 20 ~/sq and light transmission greater than 80%), as these properties can be simultaneously obtained only from a high oxygen deficiency. Based on these results, sputtering conditions are described which effectively deal with the problem. * Electrochemical Society Active Member.

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Aus wäßriger Lösung von CdSO4 und TeO, lassen sich CdTe‐Filme definierter Zusammensetzung kathodisch abscheiden.