TY - JOUR
T1 - Residual stress measurement in textured thin film by grazing-incidence X-ray diffraction
AU - Ma, C. H.
AU - Huang, J. H.
AU - Chen, H. D.
PY - 2002/10/15
Y1 - 2002/10/15
N2 -
Measurements of residual stresses in textured thin films have always been problematic. In this article, a new experimental method using grazing-incidence X-ray diffraction is presented with its principles based upon the conventional sin
2
ψ method. Instead of using the Bragg-Brentano (B-B) or Seemann-Bohlin geometry, the proposed method utilizes an asymmetrical diffraction geometry for which the X-ray beam is incident at a grazing angle γ to the sample surface, while the angle ψ is the tilt angle of the sample surface as defined by the conventional sin
2
ψ method. Basic equations involved in the X-ray residual stress analysis are described, along with exemplified experimental data. Analysis shows that, for an isotropic medium, strain measured using this grazing-incidence geometry assumes a linear relationship with the geometrical parameter cos
2
α sin
2
ψ, where the angle α is a constant and is defined as the Bragg angle at ψ = 0°, θ
o
, minus the grazing incidence angle γ, i.e. α = θ
o
-γ. The grazing-incidence diffraction geometry effectively increases the irradiation volume from a thin-film specimen, thereby giving rise to higher intensity for high-angle Bragg peaks than the conventional B-B geometry. The proposed analysis has another advantage, in that the inhomogeneous sample casts little effect on the residual stress results when compared to the traditional sin
2
ψ method.
AB -
Measurements of residual stresses in textured thin films have always been problematic. In this article, a new experimental method using grazing-incidence X-ray diffraction is presented with its principles based upon the conventional sin
2
ψ method. Instead of using the Bragg-Brentano (B-B) or Seemann-Bohlin geometry, the proposed method utilizes an asymmetrical diffraction geometry for which the X-ray beam is incident at a grazing angle γ to the sample surface, while the angle ψ is the tilt angle of the sample surface as defined by the conventional sin
2
ψ method. Basic equations involved in the X-ray residual stress analysis are described, along with exemplified experimental data. Analysis shows that, for an isotropic medium, strain measured using this grazing-incidence geometry assumes a linear relationship with the geometrical parameter cos
2
α sin
2
ψ, where the angle α is a constant and is defined as the Bragg angle at ψ = 0°, θ
o
, minus the grazing incidence angle γ, i.e. α = θ
o
-γ. The grazing-incidence diffraction geometry effectively increases the irradiation volume from a thin-film specimen, thereby giving rise to higher intensity for high-angle Bragg peaks than the conventional B-B geometry. The proposed analysis has another advantage, in that the inhomogeneous sample casts little effect on the residual stress results when compared to the traditional sin
2
ψ method.
KW - cos α sin ψ method
KW - Residual stress
KW - Textured thin film
UR - http://www.scopus.com/inward/record.url?scp=0037109204&partnerID=8YFLogxK
U2 - 10.1016/S0040-6090(02)00680-6
DO - 10.1016/S0040-6090(02)00680-6
M3 - Article
AN - SCOPUS:0037109204
VL - 418
SP - 73
EP - 78
JO - Thin Solid Films
JF - Thin Solid Films
SN - 0040-6090
IS - 2
ER -