Superhigh-Rate Epitaxial Silicon Thick Film Deposition from Trichlorosilane by Mesoplasma Chemical Vapor Deposition

• Published in: Plasma chemistry and plasma processing Vol. 33; no. 2; pp. 433 - 451
• Main Authors: Wu, Sudong, Kambara, Makoto, Yoshida, Toyonobu
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.04.2013
• Subjects: Characterization and Evaluation of Materials; Chemical vapor deposition; Chemistry; Chemistry and Materials Science; Classical Mechanics; Deposition; Epitaxial growth; Epitaxy; Flow rate; Inorganic Chemistry; Mechanical Engineering; Original Paper; Plasma processing; Silicon; Thick films; High deposition rate; Mesoplasma CVD; Epitaxial silicon film; High material yield
• ISSN: 0272-4324; 1572-8986
• DOI: 10.1007/s11090-013-9439-7

Homoepitaxial Si thick films have been deposited by mesoplasma chemical vapor deposition (CVD) with SiHCl 3 (TCS)–H 2 –Ar gas mixtures. The addition of a small amount of H 2 has been found to not only modify the film structure from polycrystalline to epitaxial but also effectively improve the deposition efficiency and film purity by removing Cl in the form of HCl. However, an excess introduction of H 2 decreases the deposition efficiency owing to the shrinkage of the plasma flame. On the other hand, an increase in TCS flow rate increases the epitaxial deposition rate despite exhibiting a saturating tendency, while the material yield tends to decrease gradually due possibly to an increase in the Cl atoms. Also, we observed a critical limit in the TCS flow rate for epitaxial growth, beyond which a polycrystalline film resulted. However, when RF input power was increased, not only the upper limit of TCS flow rate for epitaxy was extended but also the deposition yield was improved so that the deposition rate reached ~700 nm/s with the material yield of >50 % at 30 kW input power with an H 2 /TCS ratio of 1.5. Additionally, high input power is found to be beneficial to decrease Cl atom incorporation into the film and improve the Hall mobility of the films. An epitaxial film with a Cl atom concentration of less than 3 × 10 16 cm −3 and a Hall mobility as high as 250 cm 2 /(V·s) was obtained at 30 kW input power.