Lutetium oxide (Lu2O3) gate dielectric fabricated by pulsed laser deposition

• Main Author: Peter Darmawan
• Other Authors: Wang Shi Jie
• Format: Theses and Dissertations
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Nanoelectronics; DRNTU::Engineering::Electrical and electronic engineering::Semiconductors; DRNTU::Engineering::Materials::Microelectronics and semiconductor materials::Thin films; DRNTU::Engineering::Materials::Material testing and characterization
• Online Access: https://hdl.handle.net/10356/38588
• Institution: Nanyang Technological University

The aim of this project is to investigate the suitability of rare-earth oxide as gate dielectric, in particular Lu2O3. There are three main chapters, in which the properties of Lu2O3 film, the effect of post-deposition treatments on Lu2O3 film as well as the properties of Lu2O3 on the next generation of semiconductor substrate are discussed in detail. The first part covers the basic properties of Lu2O3 thin film on Si substrate. The thermal stability of Lu2O3 was investigated, in which it was able to remain thermally stable at least up to 900oC, which is close to the annealing step used in CMOS fabrication. The pulsed laser deposited (PLD) film was able to produce good electrical properties, comparable to reported work by other research groups albeit a higher interface density value. In addition, the leakage current conduction mechanism was established to be Poole- Frenkel and the effect capability of traps present in the film to trap and de-trap charges was investigated along with the effect of light illumination on the Lu2O3 MOS device. The second part of this work covers the effect of various post deposition treatment on Lu2O3. The compositional changes in the film with the introduction of rapid thermal annealing (RTA) have been investigated by employing high-resolution Rutherford backscattering spectroscopy (HRBS) measurement along with the investigation on the changes on the strain resulting from the heat treatment. Further study on the effect of heat treatment on the band alignment for the interfaces of Lu2O3/Si was also investigated in which, an increasing trend on the conduction band offset (CBO) was found. In addition, for the first time the use of laser annealing was introduced as a post deposition treatment for high-! gate dielectric film from which a significant improvement in the ! value of the Lu2O3 was obtained (about 4 times larger in magnitude). The use of laser annealing seemed to have opened up avenues for more materials to be suitable candidates for high-! gate dielectric films. The final part of this work investigates the properties of Lu2O3 on Ge, which is considered as the next generation substrate for high-speed devices due to the reported high mobility.