Ultra-shallow p+/n junction formed by plasma source ion implantation and solid boron source

Summary form only given. Using plasma source ion implantation (PSII), a novel technique has been developed to fabricate ultrashallow p/sup +//n junctions for the application of sub-micron CMOS source/drain formation. This process avoids the hazards and costs of handling highly toxic and reactive gases. In this method, a thin boron layer is first sputter deposited onto the wafer from a solid boron target. Then PSII with Ar plasma is used to knock boron atoms into the Si substrate by means of ion beam mixing. Ultrashallow p/sup +//n junctions with junction depths ranging from 27 to 85 nm have been fabricated with this technique. In addition to Ar PSII, Ne PSII has been investigated for forming shallow p/sup +//n junctions with the same technique, because Ar implantation was reported to form defects which are difficult to remove during the annealing steps. Preliminary results show that neon PSII results in more shallow boron profile, lower boron dose and higher sheet resistance.