DERIVATIZATION OF PHOTOACTIVE STRUCTURES SI( <i>N</i> <sup>+</sup>)/SI( <i>P</i>)/SI( <i>P</i> <sup>+</sup>) THROUGH ION-BEAM CRYSTALLIZATION
The physical and mathematical mass-transfer model of the ion-beam crystallization method is developed. The derivatization of photoactive structures Si(n <sup>+</sup>)/Si(p)/Si(p <sup>+</sup>) on 100 mm substrates through ion-beam crystallization is considered. The optimum conditions for the process: residual pressure in the growth chamber — 10 <sup>−4</sup> Pa; the substrate temperature — 550 °C; ion current density — 2 mA/cm <sup>2</sup>; acceleration voltage — 400 V; target — substrate distance — 150 mm are determined. The scanning electron microscopy data show that the grown photoactive structures have closely a faultless surface. The results demonstrate that the photoactive structures Si(n <sup>+</sup>)/Si(p)/Si(p <sup>+</sup>) offer the external quantum efficiency over 90 % in the wavelength range of 550—900 nm (spectrum AM 1.5) under the following conditions: front layer thickness Si(n <sup>+</sup>) — 100 nm; donor doping density n <sup>+</sup> = 5∙10 <sup>18</sup> cm <sup>−3</sup>; layer thickness Si(p) — 130 μm; acceptor doping density p = 2∙10 <sup>16</sup> cm <sup>−3</sup>; layer thickness Si(p <sup>+</sup>) — 500 nm; acceptor doping density p <sup>+</sup> = 1∙10 <sup>18</sup> cm <sup>−3</sup>.