Charge Trapping Memory with 2.85-nm Si-Nanoparticles Embedded in HfO2

Abstract

In this work, the effect of embedding 2.85-nm Si-nanoparticles charge trapping layer in between double layers of high-κ Al<inf>2</inf>O<inf>3</inf>/HfO<inf>2</inf> oxides is studied. Using high frequency (1 MHz) C-V<inf>gate</inf> measurements, the memory showed a large memory window at low program/erase voltages due to the charging of the Si-nanoparticles. The analysis of the C-V characteristics shows that mixed charges are being stored in the Si-nanoparticles where electrons get stored during the program operation while holes dominate in the Si-nanoparticles during the erase operation. Moreover, the retention characteristic of the memory is studied by measuring the memory hysteresis in time. The obtained retention characteristic (35.5% charge loss in 10 years) is due to the large conduction and valence band offsets between the Si-nanoparticles and the Al<inf>2</inf>O<inf>3</inf>/HfO<inf>2</inf> tunnel oxide. The results show that band engineering is essential in future low-power non-volatile memory devices. In addition, the results show that Si-nanoparticles are promising in memory applications.