Formation of shallow P-type layers by implantation of molecular diborane ions

Shallow p-type layers were fabricated on n-type silicon by implantation of molecular diborane ions. The ion source used was operated from B₂H₆ diluted with hydrogen. Ion species, such as B₂N₅+B₂H₄+B ₂H₃+B₂H₂+B₂H ⁺, B⁺,H⁺ and H₂⁺, generated by ion sources were implanted into Czochralski-grown 20 Ω-cm, phosphorus-doped, (100) silicon wafers at 5-25 keV using an ion-implantor without a mass-separator. The implanted silicon was annealed in Ar gas at 1000°C for 30 min. The B atom distributions became shallower with increasing dose of hydrogen ions. On the other hand, the carrier distributions became much shallower than the B atom distributions as a result that carriers diminished in the region near the B atom diffusion front