The effect of preamorphization energy on ultrashallow junction formation following ultrahigh-temperature annealing of ion-implanted silicon

High-power arc lamp design has enabled ultrahigh-temperature (UHT) annealing as an alternative to conventional rapid thermal processing (RTP) for ultrashallow junction formation. The time duration of the UHT annealing technique is significantly reduced from those obtained through conventional RTP. This difference in time may offer the ability to maintain a highly activated ultrashallow junction without being subjected to transient enhanced diffusion (TED), which is typically observed during postimplant thermal processing. In this study, two 200 - mm (100) n -type Czochralski-grown Si wafers were preamorphized with either a 48- or a 5 - keV Ge + implant to 5 × 10 14 cm 2 , and subsequently implanted with 3 - keV B F 2 + molecular ions to 6 × 10 14 cm 2 . The wafers were sectioned and annealed under various conditions in order to investigate the effects of the UHT annealing technique on the resulting junction characteristics. The main point of the paper is to show that the UHT annealing technique is capable of producing a highly activated p -type source∕drain extension without being subjected to TED only when the preamorphization implant is sufficiently deep.