Diode analysis of high-energy boron implantation-induced P-well defects

The use of a p-n junction diode as a tool for the assessment of the p-well quality is demonstrated, by analyzing in detail the current-voltage and cap acitance-voltage characteristics of n(+)-p-well junctions surrounded by eit her shallow trench isolation or polysilicon encapsulated local oxidation of silicon. As a reference, diodes fabricated in a p-type substrate and defin ed by a local oxidation of silicon isolation have been used. Particular emp hasis is on the lifetime properties and leakage current activation energy o f the p-well region, which has been fabricated by a deep (200 keV) and a sh allow (55 keV) boron ion implantation. That the leakage current of large ar ea diodes is governed by electric field-assisted generation of carriers fro m residual, unannealed deep B-implantation damage is demonstrated. The pres ence of such defects is confirmed by deep level transient spectroscopy anal ysis. The generation lifetime profile in the depletion region and the rever se current activation energy are extracted by taking account of the, electr ic field enhancement factor of the thermal generation. Finally, it is shown that the generation lifetime and residual defects depend mainly on the glo bal thermal budget and little on the isolation scheme used. (C) 2001 The El ectrochemical Society.