Arvind Halliyal

Quantum-well memory device (QWMD) with extremely good charge retention

We propose and demonstrate a new device that utilizes a quantum well (its dimensions determined by two self-limiting processes) as a floating gate. We show that fast programming and erasing can be achieved. Excellent charge retention (ten years) is obtained, for 2.7 nm thin tunneling oxide, at room temperature, and for 5 nm thin tunneling oxide even at elevated temperature.

Optical Analyses (SE and ATR) and Other Properties of LPCVD Si3 N 4 Thin Films

Thin silicon nitride films (less than 20 nm) deposited on (100) silicon substrates via low pressure chemical vapor deposition (LPCVD) at three temperatures (730, 760, and 825°C) were analyzed by spectroscopic ellipsometry (SE), attenuated total reflection (ATR), and other tools. Films appeared to have similar optical bandgaps (∼5 eV). and the values decreased slightly with the higher deposition temperature. Second ionic mass spectroscopy results showed that a similar amount of oxygen exists in the interface between silicon and silicon nitride. ATR spectra showed no sign of Si-H bonds and decreasing N-H bonds at higher deposition temperature in the thin films. The electrical properties of the films are also discussed.