CVD Delta-Doped Boron Surface Layers for Ultra-Shallow Junction Formation

A new doping technique is presented that uses a pure boron atmospheric/low-pressure chemical vapor deposition (AP/LPCVD) in a commercially available epitaxial reactor to form less than 2-nm-thick ?-doped boron-silicide (BxSi) layers on the silicon surface. For long exposure B segregates at the surface to form a very slow growing amorphous layer of pure B (?-B). The electrical properties of the as-deposited ?- B/BxSi stack have been studied by fabricating and measuring diodes where the B depositions are formed directly in the diode contact windows for different exposure times. It is demonstrated that the presented doping technique can be used to form high-quality ?-doped p+n junctions. Moreover, the formed ?-B/BxSi layer is an attractive source of high-concentration B dopants for thermal annealing processes that does not induce any transient-enhanced diffusion (TED) effects.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc