Variable-energy positron lifetime study of silicon-oxide films plasma deposited from hexamethyldisiloxane and oxygen mixtures

✍ Scribed by C. L. Wang; Y. Kobayashi; H. Togashi; K. Hirata; R. Suzuki; T. Ohdaira; T. Mikado; S. Hishita

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 179 KB
• Volume: 79
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/1097-4628(20010207)79:6<974::aid-app30>3.0.co;2-d

✦ Synopsis

Mixtures of hexamethyldisiloxane [HMDSiO, (CH 3 ) 3 SiOSi(CH 3 ) 3 ] and oxygen are plasma polymerized at different oxygen pressures (P O 2 ϭ 1.3-11.4 Pa) and a fixed monomer pressure (P m ϭ 2.6 Pa). The discharge power is kept at 100 W throughout the work. Nanometer-size holes in the deposited films are characterized by variableenergy positron annihilation lifetime spectroscopy (PALS). Additional information on the film composition and structure is obtained by X-ray photoelectron spectroscopy and IR absorption spectroscopy. The ortho-positronium lifetime 3 and intensity I 3 increase with the P O 2 up to 6.2 Pa and then decrease with the P O 2 . PALS measurements after annealing at 400°C show that films prepared at high oxygen pressure have a less stable structure than a film deposited at a lower oxygen pressure. These results are discussed in comparison with plasma deposition of pure HMDSiO, as are the possible effects of oxygen radicals on the film structure.