SiO2 gate dielectric layers (4–60 nm) were grown (0.6 nm/min) by plasma-enhanced chemical vapor deposition (PECVD) in strongly diluted silane plasmas at low substrate temperatures. In contrast to the well-accepted positive charge for thermally grown silicon dioxide, the net oxide charge was negative and a function of layer thickness. Our experiments suggested that the negative charge was created due to unavoidable oxidation of the silicon surface by plasma species, and the CVD component added a positive space charge to the deposited oxide. The net charge was negative under process conditions where plasma oxidation played a major role. Such conditions include low deposition rates and the growth of relatively thin layers.
- SC-ICF: Integrated Circuit Fabrication
Boogaard, A., Kovalgin, A. Y., & Wolters, R. A. M. (2009). Net Negative Charge in low-temperature SiO2 gate dielectric layers. Microelectronic engineering, 86(7-9), 1707-1710. [10.1016/j.mee.2009.03.124]. https://doi.org/10.1016/j.mee.2009.03.124