Effect of radio frequency power on the properties of hydrogenated amorphous carbon films grown by radio frequency plasma-enhanced chemical vapor deposition

被引:26
作者
Hayashi, Y
Hagimoto, K
Ebisu, H
Kalaga, MK
Soga, T
Umeno, M
Jimbo, T
机构
[1] Nagoya Inst Technol, Dept Environm & Urban Planning, Showa Ku, Nagoya, Aichi 4668555, Japan
[2] Nagoya Inst Technol, Dept Elect & Comp Engn, Showa Ku, Nagoya, Aichi 4668555, Japan
[3] Nagoya Inst Technol, Res Ctr Microstruct Devices, Showa Ku, Nagoya, Aichi 4668555, Japan
[4] Toyota Technol Inst, Semicond Lab, Tempaku Ku, Nagoya, Aichi 4688511, Japan
来源
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS | 2000年 / 39卷 / 7A期
关键词
RF plasma-enhanced CVD; amorphous carbon; ESR; FT-IR; photoluminescence;
D O I
10.1143/JJAP.39.4088
中图分类号
O59 [应用物理学];
学科分类号
摘要
We have studied the influence of radio frequency (RF) power on material properties of hydrogenated amorphous carbon (a-C:H) films prepared by RF plasma-enhanced chemical vapor deposition (CVD). The RF power has a significant impact on film properties such as electron spin resonance (ESR) spin density, the optical band gap, chemical bonding and photoluminescence (PL). Raman spectroscopy, infrared (IR) absorption and ESR measurements reveal that the residual defect density (ESR spin density) increases with increasing RF power due to the increase of sp(2) C-H-x components. We obtained an ESR spin density as small as 8 x 10(16) spins/cm(3) at a low RF power, which is comparable to that of high-quality amorphous silicon films. Plasma optical emission spectroscopy indicates that the intensity ratio (IC-H/I-H) between hydrogen peaks (I-H) and hydrocarbon peaks (IC-H) significantly decreases with increasing RF power. The optical band gap, obtained from UV-visible spectroscopy, varies from 3.0 to 1.9 eV with increasing RF power. The broad emission band centered around 2.4 eV was observed in the PL spectra of the samples deposited at lower RF powers. We found a 0.5-0.3 eV Stokes shift by comparing the PL emission and the absorption coefficient spectrum from the films deposited at less than or equal to 100W RF powers, whereas, we failed to observe a clear Stokes shift from the films deposited at >100W RF powers. A weak correlation between the PL peak and the optical band gap is demonstrated.
引用
收藏
页码:4088 / 4093
页数:6
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