Ion-implanted phosphorous in silicon: profiles using C--V analysis

Depth distributions are presented for 200-, 300-, and 600-keV phosphorus ions either channeled along the 〈111〉 axis or implanted away from any major axis or plane in silicon. The profiles were obtained using the differential capacitance technique, and the technique is discussed along with a description of an automatic data-acquisition system which allows precise C-V data to be accumulated. The ``random''-direction implant profiles exhibit a definite exponential tail on the deep side of the implant. The characteristics of this tail appear to be material dependent but independent of the implantation energy. Thus, the tail probably results from an anomalous diffusion mechanism. The observed projected range for the random implants is 1.1 μm/MeV, with a range straggle nearly equal to that predicted by the range theory of Lindhard, Scharff, and Schiott (LSS). The channeled profiles exhibit a near flat characteristic to a depth of 2.2 μm/(MeV)1/2.