Superior NBTI in High- $k$ SiGe Transistors–Part I: Experimental
| Autor: | Tibor Grasser, Liesbeth Witters, W. Goes, A. Grill, B. Kaczer, Michael Waltl, J. Franco, Jerome Mitard, Gerhard Rzepa, Naoto Horiguchi |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Negative-bias temperature instability Materials science business.industry Transistor 02 engineering and technology Dielectric 021001 nanoscience & nanotechnology 01 natural sciences Electronic Optical and Magnetic Materials Silicon-germanium law.invention Threshold voltage chemistry.chemical_compound chemistry Stack (abstract data type) law Logic gate 0103 physical sciences Electronic engineering Optoelectronics Electrical and Electronic Engineering 0210 nano-technology business High-κ dielectric |
| Zdroj: | IEEE Transactions on Electron Devices. 64:2092-2098 |
| ISSN: | 1557-9646 0018-9383 |
| Popis: | SiGe quantum-well pMOSFETs have recently been introduced for enhanced performance of transistors. Quite surprisingly, a significant reduction in negative bias temperature instability (NBTI) was also found in these devices. Furthermore, a stronger oxide field acceleration of the degradation in SiGe devices compared with Si devices was reported. These observations were speculated to be a consequence of the energetical realignment of the SiGe channel with respect to the dielectric stack. As these observations were made on large-area devices, only the average contribution of many defects to NBTI could be studied. In order to reveal the microscopic reasons responsible for the improved reliability, a detailed study of single defects is performed in nanoscale devices. To provide a detailed picture of single charge trapping, the step-height distributions for different device variants are measured and found to follow a unimodal and bimodal distribution. This finding suggests two conducting channels, one in the SiGe and one in the thin Si cap layer. We, furthermore, demonstrate that similar trap depth distributions are present among the device variants supported by a similar stress bias dependence of the capture times of the identified single defects. We conclude that NBTI is primarily determined by the dielectric stack and not by the device technology. |
| Databáze: | OpenAIRE |
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