As part of the program to develop a large-area thin-film pulse heater for a lithium ion source, the residual stress in post cathode magnetron sputter deposited molybdenum films has been studied. It was found that in films prepared in the low-pressure sputtering regime, the residual film stress is very sensitive to the gas pressure during sputtering and that the film stresses are highly anisotropic. The transition pressure for changing from compressive to tensile residual stress, as defined by Thornton and Hoffman, depends on the relationship between the measurement direction in the film and the post cathode orientation. In order to deposit a nearly stress-free film a pressure cycling technique was developed which deposited alternate film layers containing tensile and compressive stresses. Film resistivity and thermal coefficient of resistivity measurements were made during the pulse heating of the molybdenum films.

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A pulsed, large area, Li vapor source for use in the PBFA-II ion beam diode is described. BOLVAPS (boil-off lithium vapor source) produces a 1–2 mm thick layer of Li vapor with a density approaching 1×1017 cm−3 by rapid ohmic heating of a thin-film laminate, one layer of which contains Li. The principal design issues of the vapor source being built for use on the PBFA-II accelerator are described. Results of small-scale development experiments are summarized.

We have demonstrated the possibility of depositing thick molybdenum films closed−end insulating tube using the post cathode magnetron sputter deposi tion configuration using a high sputtering gas pressure an a means for rem oving the surface charge buildup. (AIP)