Shallow Donor Formation In Hydrogen-Implanted Silicon

Abstract

AbstractFormation of shallow donors has been studied in 100-keV hydrogen-implanted n-type silicon with a dose of 1×1015 cm−2. Annealing experiments are made in the temperature range 100 to 800°C. Gold Schottky contacts are fabricated on these samples to obtain carrier concentration profiles. The hydrogen profiles are measured by secondary ion mass spectroscopy. In the annealing temperature range 350 to 450°C, an increase of the carrier concentration is observed near the surface region with almost flat depth profiles. The well- known hydrogen-related donors (1st shallow donors) disappear around 400°C, while shallow donors (2nd shallow donors)observed here decrease above 500 °C. Hydrogen profiles show almost no change in the 2nd donor formation temperatures, although hydrogen starts to outdiffuse at 250°C. This indicates that the 2nd shallow donors are related to hydrogen atoms and to implantation-induced damage. The implantation-induced defects trap diffusing hydrogen atoms, which leads to the formation of the 2nd shallow donors.