Depth-dependent characterization and modeling of POCl3-doped polysilicon deposited by low-pressure chemical vapor deposition
Thin Solid Films, cilt.849, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 849
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.tsf.2026.141015
- Dergi Adı: Thin Solid Films
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Depth-dependent characterization, Electrically active dopant profile, Four-point probe, FTIR spectroscopy, LPCVD polysilicon, POCl3doping, Raman spectroscopy, Residual stress, TCAD simulation
- Marmara Üniversitesi Adresli: Evet
Özet
In this study, polysilicon films deposited via Low-Pressure Chemical Vapor Deposition were doped with phosphorus through POCl3 diffusion, and the depth-dependent distribution of electrically active dopants was investigated using a comprehensive characterization approach coupled with controlled etching steps. The initial film, approximately 450 nm thick, was progressively thinned through sequential etching, and at each stage, structural, chemical, optical, mechanical, and electrical properties were systematically evaluated. Raman spectroscopy confirmed the polycrystalline nature of the films, while Scanning Electron Microscopy revealed the microstructural evolution induced by doping and etching processes. Fourier Transform Infrared spectroscopy qualitatively identified phosphorus-related bonding; the absence of phosphorus-oxygen bonds in the gate oxide layer indicates that SiO2 maintains its role as an effective diffusion barrier. Profilometry measurements indicated that residual stress within the films increased as the thickness decreased. Sheet resistance values obtained from four-point probe measurements were used to calculate the resistivity and electrically active carrier concentration via semi-empirical physical relationships, allowing the depth-dependent evolution of electrical parameters to be assessed. The observed trends indicate that the electrically active carrier concentration is higher near the film surface and gradually decreases with depth. Technology Computer-Aided Design simulations employing a mobility model incorporating grain-boundary barrier effects reproduced the experimentally observed carrier transport behavior.This study demonstrates that, by combining etching-based characterization with multiple physical measurement techniques, the depth-dependent electrical behavior of doped polysilicon films can be holistically evaluated without requiring direct chemical profile analysis.