Non-destructive optical methods for assessing defects in production of Si or SiGe materials

¹ Accent Optical Technologies UK Ltd, Hemel Hempstead, HP2 7DF, UK
² ST Microelectronics, 850 rue Jean Monnet, 38926 Crolles, France

Corresponding author: victorh@hi-techsci.com

Received: 14 August 2003
Accepted: 10 February 2004
Published online: 15 July 2004

Abstract

Non-destructive techniques are ideal for process control and process development. They do not involve any special wafer treatment and the wafers can be further processed in the manufacturing line. A relatively new technique that can be applied to materials characterizations is room temperature photoluminescence (RT-PL). Defects can be revealed because of the enhanced non-radiative recombination at the defect site. The efficiency of detecting defects in SiGe was evaluated. Defects could be detected in blanket film SiGe layers, and there was a good correlation with bright field microscopy inspection and laser scanning methods. The effect of ex-situ cleaning, pre-bake and Boron doping conditions have been investigated. The results follow the expected trends, more defects for non-standard processing. The defects detected by RT-PL were confirmed using transmission electron microscopy (TEM). Defects could also be detected in part-processed patterned wafers, giving a direct indication of the material quality in product wafers.