Enhanced electrical activation of indium coimplanted with carbon in a silicon substrate

Abstract

Electrical activation of In of 18%–52% of the implanted dose (531014 cm-²) was obtained in Si samples having a C+ coimplantation after rapid thermal annealing (RTA) at 800–1000 °C for 15 s. This electrical activation yield markedly contrasts with that in samples singly implanted with In in which only ~=0.5% of the dose was activated. The following features were observed in the coimplanted samples: (i) a reverse annealing of the electrical activation in the temperature range of 800–900 °C; (ii) significant reduction of the In profile redistribution during RTA; and (iii) the electrically activated In concentration is substantially higher than the substitutional In concentration. These findings are discussed in terms of the interaction between C atoms and Si self-interstitials (SiI), strain compensation between C and In atoms in the Si lattice, and formation of stable In substitutional–C substitutional acceptors centers.