Plasma doping for shallow junctions

In this article we review the characteristics of ultrashallow junctions produced by plasma doping (PLAD). PLAD is one of the alternate doping techniques being developed for sub-0.18 mu m devices. Here, we describe results from a wide range of experiments aimed at the production of ultrashallow junctions. For the results shown here, a BF3 plasma was used to provide the dopant ions that were implanted into 150 and 200 mm Si substrates using wafer biases ranging from -0.14 to -5.0 kV. The ultrashallow junctions formed with this technique have been examined with both secondary ion mass spectrometry and electrical profiling techniques. Good sheet resistance uniformity, charging performance, structural quality, and photoresist integrity have been obtained. When PLAD is used in the production of sub-0.2 mu m gate length p-metal-oxide-semiconductor field effect transistors, one finds subthreshold swing, off-state leakage, and hot-carrier reliability that are similar to beamline-implanted ones. In addition, higher drive currents an seen in the plasma-doped devices. (C) 1999 American Vacuum Society. [S0734-211X(99)06505-1].