抄録
The impurity profile near the interface was determined for N on N+ silicon epitaxial layers by a new method which is based on the observation of infrared interference fringes.
The relation between the wavenumber of the highest order fringe in the visible fringes and the impurity gradient at the depth where the impurity concentration N is equal to 1018/cc was studied for heat-treated wafers which had been grown by the SiH4 method, based on the assumption that the impurity redistribution is of the error function type. Making use of the above relation, the impurity profile in wafers prepared by the SiCl4 method was evaluated. If the error function type distribution is admitted, the result can be expressed approximately by N=exp(ax+b), where x is the coordinate normal to the surface and a and b are constants. This equation is in good agreement with the result of the C–V measurement.
