Abstract
Silicon dioxide (SiO2) gate dielectric layers (4-60 nm thick) were deposited (0.6 nm/min) on n-type Si by inductively-coupled plasmaenhanced chemical vapor deposition (ICPECVD) in strongly diluted silane plasmas at 150°C . In contrast to the well-accepted positive charge for thermally grown SiO2, the net oxide charge was negative and a function of the 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 adding 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 included low deposition rates and relatively thin grown layers. Additional measurements showed that the negative charge in SiO2 also persisted on p-type substrates. We suggest that plasma oxidation of the silicon surface results in SiO2 layers with a surplus of oxygen.
This surplus of oxygen is able to accumulate a negative charge. This assumption is addressed in this paper by a review of earlier work on silicon oxidation, and by a first series of experiments wherein oxygen is implanted into thermal SiO2. It is shown that the implantation can result in a negative charge to the bulk oxide layer. The effect of the negative charge on the flatband voltage can be described by the implantation profile.
Original language | Undefined |
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Title of host publication | 219th ECS Meeting |
Place of Publication | USA |
Publisher | The Electrochemical Society Inc. |
Pages | 259-272 |
Number of pages | 14 |
DOIs | |
Publication status | Published - 1 Jul 2011 |
Event | 219th ECS Meeting - The Palais des Congres de Montreal, Montreal, QC, Canada Duration: 1 May 2011 → 6 May 2011 Conference number: 219 |
Publication series
Name | ECS Meeting Abstracts |
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Publisher | The Electrochemical Society |
Number | 4 |
Volume | 35 |
ISSN (Print) | 1938-5862 |
ISSN (Electronic) | 1938-6737 |
Conference
Conference | 219th ECS Meeting |
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Country | Canada |
City | Montreal, QC |
Period | 1/05/11 → 6/05/11 |