Measurement of the electrical impurity profile of implanted ions, using the pulsed MOS C-V technique

The differential capacitance technique used on a MOS structure with a pulsed bias applied, is well suited for the determination of low dose impurity implantations. It is a nondestructive method and requires no extra processing steps. The limitations restricting the use of this technique are discussed. It is shown that for steep profiles a corrrection due to the existence of a diffusion potential has to be taken into account. The range in which this diffusion voltage is important is the same as for the correction proposed by Kennedy and O'Brien (IBM J. Res. Div.; 13:212 (1969)) which arises from the difference between the impurity profile and the majority carrier profile in the quasi-neutral condition. The method of calculation, and the experimental verification are discussed. (author)