Thick and stress-free Sendust films on silicon for recording head cores

LETI´s recording heads technology requires the deposition of thick Sendust films on silicon substrates, both materials having very different thermal expansion coefficients. Despite of this unfavorable condition, adherent and stress-controlled films, up to 10 μm thick, have first been obtained by facing target sputtering under Ar+ nitrogen atmosphere whose influence is great on films´ microstructure. Stress-free state has then been achieved by cumulative rapid thermal annealing when starting from compressive stress-induced films