Formation of Thin Germanium Dioxide Film with a High-Quality Interface Using a Direct Neutral Beam Oxidation Process

摘要

A damage-free and low-temperature neutral beam oxidation (NBO) process is used to directly form a thin germanium dioxide (GeO_2) film. A GeO_2 film with only a small amount of suboxide is formed even at a low substrate temperature of 300 ℃ because of the extremely low-activation-energy oxidation owing to bombardment with 5-eV-energy oxygen neutral beams. We combined the NBO process with hydrogen radical native oxide removal treatment to form high-quality GeO_2 films, and our fabricated Al_2O_3/GeO_2/Ge gate stack has an extremely low interface state density (D_(it)) of less than 1 × 10~(11) cm~(-2) eV~(-1).