Formation of NiSi-silicided shallow p +n junctions by BF 2+ implantation into thin Ni or NiSi Films on Si substrates and subsequent anneal

Abstract

A low-temperature process scheme for fabricating silicided shallow p +n junctions is described and investigated. The formation scheme is that BF 2 + ion implantation into thin Ni or NiSi films deposited on a Si substrate and subsequent anneal. An NiSi silicided shallow p +n junction with a leakage of about 4 nA cm −2 at −5 V and a forward ideality factor of about 1.01 can be obtained by just annealing the sample with implantation into thin NiSi films at 600°C for 30 min. Accordingly, an NiSi sheet resistivity of about 22 μΩ-cm can be obtained. Though the sample with implantation into thin Ni films can also lead to good junction, the silicide is slightly degraded causing an increase of resistivity to about 30 μΩ-cm. For these schemes, rapid thermal annealing is found to be less effective in forming junctions than conventional furnace annealing.