Donor center formation in silicon implanted with hydrogen ions

We have studied the electrical properties of Schottky diodes based on epitaxial n-Si films irradiated by low-energy (300 keV) hydrogen ions. The implantation of protons at room temperature leads to the formation of shallow donors whose concentration-depth profile coincides with that of the incorporated hydrogen. These donor centers are stable on heating up to 150degreesC and are completely annealed at a temperature of about 250degreesC. Heating above 270degreesC leads to the formation of well-known donor centers with a concentration more than two times that of the centers of the first type. Donors of the second type are annealed in two stages at 375- 425 and 450-525degreesC. The nature of the donor centers of both types is related to the formation and transformation of two-dimensional hydrogen-containing defects in a radiation-damaged crystal. (C) 2004 MAIK "Nauka/Interperiodica".