The investigation and analysis of the electrical conduction mechanism for polycrystalline diamond films

• Main Authors: Chou Wei-Hua, 周維華
• Other Authors: Huang Bohr- Ran
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/61032085782673655440

碩士 === 國立雲林科技大學 === 電子工程與資訊工程技術研究所 === 88 === The poly-crystalline diamond thin films were deposited on silicon substrate by microwave plasma chemical vapor deposition system (MPCVD) using methane-hydrogen gas mixtures. Prior to deposition the silicon substrates were seeded by photoresist in which 0.1 micron diamond powder is suspended. After deposition, the polycrystalline diamond films were doped by boron ion implantation (80 Kev, 5.0 ×1015 cm-2) and were annealed under 800-oC in N2 for 1h. From the ESCA analyses, it was found that the oxygen signal appeared in addition to the carbon signal for the un-doped and B-doped polycrystalline diamond films. It was also observed that the oxygen signal increases a lot, the carbon signal became very small and the silicon signal showed up appreciably after the 800℃ annealing process. In this research, a conduction mechanism was successfully established for the Al/un-doped and Al/B-doped diamond films. It was found that Al/un-doped diamond exhibited rectifying properties at room temperature and more ohmic behavior as temperature increased. However, Al/ B-doped diamond exhibited ohmic properties in the temperature range of 30 and 300℃. The modified equivalent circuit model of the Al/ diamond structure was an ideal Schottky diode in series with the impedance ZL, which was formed by the bulk diamond resistance in parallel with the diamond grain boundaries resistance and it was found to be temperature-dependent. It was found that the impedance ZL can be represented by the field activated transport mechanism, which can be expressed by the Frankel-Poole equation.