Abstract
Recently, many efforts have been made to improve the device performance of nanocrystal memory by replacing the SiO2with various high dielectric constant (high-k) materials, especially embedded with Ge nanocrystals. This paper demonstrates the floating gate memory effect by embedding nanometer-sized Ge nanocrystals in hafnium aluminate (HfAlO) high-fe gate dielectric. A 5 nm-thick amorphous thin film of HfAlO was first deposited on (100) p-Si substrates as a tunneling gate oxide layer by laser molecular beam epitaxy deposition using a HfO2and A12O3composite target. Well-defined (∼10 nm in diameter) nanometer-sized Ge dots were subsequently deposited on this thin tunneling gate oxide followed by a 30 nm-thick top control gate oxide of HfAlO. Transmission electron microscopy has been carried out for a detailed study of structural properties of the Ge nanocrystals embedded in the HfAlO films, and their relationships to electrical properties. Electrical properties have been characterized by means of high-frequency capacitance-voltage (C-V) and current-voltage (I-V) measurements on the metal-oxide-semiconductor capacitors. A counter-clockwise hysteresis C-V loop has been obtained and a threshold voltage shift of 1.0 V has been achieved indicating stored electrons (up to a density of 2×1012cm-2) in the Ge-nanodots floating gate and thus the memory effect. Time-dependent I-V measurement also showed low leakage current of floating gate system. These results suggest that the Ge nanocrystals embedded in HfAlO are promising for floating gate memory device application.
Original language | English |
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Article number | 63 |
Pages (from-to) | 150-155 |
Number of pages | 6 |
Journal | Proceedings of SPIE - The International Society for Optical Engineering |
Volume | 5650 |
DOIs | |
Publication status | Published - 20 Jun 2005 |
Event | Micro- and Nanotechnology: Materials, Processes, Packaging, and Systems II - Sydney, Australia Duration: 13 Dec 2004 → 15 Dec 2004 |
Keywords
- Floating gate memory
- Ge nanocrystals
- HfAlO
- High-k dielectrics
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering