Enhanced mobility in SOI films annealed by rapid thermal annealing

• Published in: Applied surface science 1989, Vol.36 (1), p.572-578
• Main Authors: Almaggoussi, A., Sicart, J., Robert, J.L., Joly, J.F., Laugier, A.
• Format: Article
• Language: English
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/0169-4332(89)90952-5

Rapid thermal anneals (RTA) have been performed on boron-implanted LPCVD polysilicon films. The influence of the heat-treatment on the electrical properties is examined in order to study the difference between RTA and conventional thermal anneal (CTA) processes through the electrical activity of the grain boundary (GB) barriers. Van der Pauw and Hall measurements have been carried out on RTA and CTA annealed films. The mobility in RTA films is even higher than that measured in silicon single crystals with comparable dopant concentration. This enhanced mobility in the RTA process is interpreted by a simple model based on the non-uniform distribution of boron in the grains. On the contrary, during the CTA process, boron is uniformly redistributed in the grains, resulting in the formation of an electrically active GB barrier. Therefore, RTA seems to be a very promising annealing process increasing the carrier mobility in SOI layers.