The Study of High-Density Plasma Treatment on Nanocrystal Memory Cell with Si and Ge Substrates

In order to scale down the floating gate (FG) nonvolatile memory (NVM), tunnel oxide limitation for sufficient charge retention has to be overcome. One is to implement high dielectric constant (high-k) materials as the tunnel oxide for the reduction of operation voltage while satisfying the data retention and endurance. The other is using discrete charge storage concept for thinner tunnel oxide without sacrificing nonvolatility. Nanocrystal (NC) memories are kinds of such NVMs that have been demonstrated to have a more simplified fabrication process, better punchthrough effect and immunity to oxide defects as compared to conventional FG NVMs. To achieve the fast write/erase and long retention time simultaneously, metal NC memories are presented. Recently, high-k dielectric NC memories are proposed to exhibits better characteristics than the metal counterparts. In this project, we will apply a new Gd2O3 high-k dielectric NC memory with some advanced techniques to improve the electrical characteristics. In addition, the optimized design of this Gd2O3 NC memory with different substrate will also be studied. The main project items are shown as following: 1. A new Gd2O3 high-k dielectric NC memory with optimized process conditions is studied. Electrical and physical properties will be measured and discussed. 2. The memory will be treated by nitrided and fluorinated plasma. The plasma treatment conditions will be evaluated. 3. By using the Gd2O3 NC memory on n-type and p-type silicon substrate, the physical models will be proposed. 4. We will use the Ge substrate to enhance the program and erase efficiency for Gd2O3 NC memory. Besides, the physical models for Ge substrate will be demonstrated and compared to the Si one.

Project ID:PB9803-0109
External Project ID:NSC98-2218-E182-002-MY2