Effect of MeV nitrogen ion implantation on the resistivity transition in Czochralski silicon wafers

Abstract

We investigated how MeV nitrogen ion implantation affects the resistivity transition in Czochralski (CZ) silicon wafers. After annealing at 800 °C for 20 h and again at 1000 °C for 10 h, the implanted nitrogen atoms accumulated in the projected range (RP) for ion doses less than 5 × 1014 cm−2 whereas they accumulated at both RP/2 and RP at ion doses above 3 × 1015 cm−2. These results indicate that no resistivity transition was found at nitrogen ion doses less than 5 × 1013 cm−2 whereas n−/p or n+/p resistivity transition was shown at ion doses higher than 5 × 1014 cm−2. Many fewer than 1% of the implanted nitrogen atoms were ionized after the heat treatment. Thus, the resistivity of nitrogen-doped silicon wafers is more than 100 times higher than that of phosphorous-doped silicon wafers.