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Journal Articles Applied Surface Science Year : 1989

Stresses, microstructure and resistivity of thin tungsten films deposited by RF magnetron sputtering

Abstract

High-deposition rate magnetron sputtering is used to study the properties of tungsten films deposited in a dynamic mode from a 99.95% pure target in a multitarget production system equipped with a loadlock chamber and a cryopump. Films are deposited on BPSG covered silicon wafers. The electrical resistivity and stress of these films have been related to the film microstructure, composition and to the deposition conditions (RF power and substrate bias). A −150 V bias voltage is necessary to maintain lower resistivity (0.09 μΩ m): the resistivity of films deposited at a low power density (1.7 W cm−2) decreases with increasing thickness, from 0.50 μΩ m for 50 nm thick films to 0.09 μΩ m for thicker ones (> 200 nm). Typical stress of unbiased films 250 nm thick deposited at 1.7 W cm−2 is 900 MPa tensile and becomes compressive either by increasing the power density (−4000 MPa at 5.6 W cm−2) or by applying a negative bias to the substrate (−1400 MPa for −150 V bias voltage). Moreover, at 1.7 W cm−2, stresses reach zero under −50 V bias for a critical film thickness, which is in our experimental conditions, around 300 nm. It is found that the stress in the film containing the β-W phase is either tensile or compressive, the films consisting of α-W are always compressively stressed.

Dates and versions

hal-04602063 , version 1 (05-06-2024)

Identifiers

Cite

M.C. Hugon, F. Varniere, B. Agius, Michel Froment, C. Arena, et al.. Stresses, microstructure and resistivity of thin tungsten films deposited by RF magnetron sputtering. Applied Surface Science, 1989, 38 (1-4), pp.269-285. ⟨10.1016/0169-4332(89)90548-5⟩. ⟨hal-04602063⟩
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