Semiconductor analysis with a channeled helium mmicrobeam

This paper describes the use of a channeled helium microbeam for analysis of damage and dopant distributions in semiconductors. Practical difficulties and potential problems associated with the channeling of microbeams in semiconductors have been examined. In particular, the following factors have been characterised: (1) the effect of both convergence of focused beam and beam scanning on the quality of channeling; (2) damage produced by the probe ions; and (3) local beam heating effects arising from high current densities. Acceptable channeling has been obtained (minimum yield approaching 4%) under a variety of focusing and scanning conditions which are suitable for analysis of device structures. The capabilities of the technique are demontrated by monitoring variations in local damage and impuritiy depth distribution across a narrow (<2 mm) region of an ion implanted silicon wafer. (orig.)