The use of convergent beam electron diffraction for stress measurements inshallow trench isolation structures

Shallow trench isolation (STI) is a promising technology for the isolation structures of the new generation of ULSI devices with dimensions below 0.18 mum. The various processing steps cause stress fields in STI structures, w hich can lead to defect formation in the silicon substrate. In their turn, stress fields affect the electrical parameters and the reliability of devic es. Convergent beam electron diffraction (CBED) is used in this study to ex amine the influence of a wet and a dry pre-gate oxidation on the stress dis tribution around STI structures. The measurements are performed on STI stru ctures with different width and spacing. CBED analysis is compared with bri ght-field TEM images. Defects are observed in high-strain areas of small is olated structures. (C) 2001 Elsevier Science Ltd. All rights reserved.