An experimental technique for the measurement of two‐dimensional impurity diffusion profiles in silicon has been developed. Both the lateral and in‐depth extent of dopant diffusion under a mask edge are magnified mechanically by sawing and angle lapping, and the magnified junction contour is delineated by chemical staining. The two‐dimensional shape of the junction is reconstructed from the measured stained contour. A complete diffusion profile consisting of several isoconcentration contours can be obtained by measuring the junction shape on a series of samples with increasing substrate resistivities, provided the doping level in the substrate does not affect the diffusion of the impurity under study. Results of the two‐dimensional diffusion of boron in silicon at 1050 °C are presented.
[1]
Franklin F. Y. Wang,et al.
Impurity doping processes in silicon
,
1981
.
[2]
B. R. Wilkins,et al.
Direct Observations of n‐MOSFET Channel Lengths
,
1987
.
[3]
D. C. Gupta,et al.
Semiconductor fabrication : technology and metrology
,
1989
.
[4]
Apparatus for the Measurement of Small Angles
,
1972
.
[5]
U. Gösele,et al.
Two-dimensional phosphorus diffusion for soft drains in silicon MOS transistors
,
1986
.
[6]
H. Leamy,et al.
Charge collection scanning electron microscopy
,
1982
.