Study of High-k Materials as Trapping Layer Combined with Rapid Thermal Annealing for Nonvolatile Memory Application

• Main Authors: Chuang Chih Sheng, 莊志勝
• Other Authors: C. H. Kao
• Format: Others
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/75192360131549330508

碩士 === 長庚大學 === 電子工程學研究所 === 97 === In this paper, we use high-k dielectric material as flash memory charge trapping layer. The high dielectric coefficient material, Titanium and Hafnium intermix with Titanium and Tantalum using sputtering to form metal oxide charge trapping layer. Meanwhile, we discuss these three kinds of metal with high dielectric coefficient as charge-trapping layer. To compare with their physical and electrical property, these three kinds of devices are composed by tunneling oxide (silicon dioxide) – charge trapping layer – control oxide (silicon dioxide) with same thicknesses (3nm, 12nm, 10nm, respectively). Through different RTA process, the memory window of Titanium nonvolatile memory are larger than Hafnium intermix with Titanium and Tantalum, but window of Titanium and Tantalum nonvolatile memory will shrink while annealing temperature arises. And the memory window of Hafnium intermix with Titanium nonvolatile memory device will increase with annealing temperature arise. According to experiment, Hafnium intermix with Titanium nonvolatile memory device obtain better thermal stability. Among these three kinds of memory, Titanium and Hafnium intermix with Titanium program speed can be at 1ms, and erase speed is about 3~5s, the erase speed of Titanium nonvolatile flash memory is quicker than Titanium and Hafnium intermix, and the program speed of Tantalum nonvolatile flash memory can up to 1ms, and erase speed is about 3s. Tantalum nonvolatile flash memory obtain better retention time than Hafnium intermix with Titanium and Tantalum nonvolatile flash memory at both room temperature and 85ºC. And charge-loss rate of Tantalum nonvolatile flash memory are less than Hafnium intermix with Titanium and Tantalum nonvolatile flash memory. The experiment results proved that no matter Tantalum nonvolatile flash memory, Hafnium intermix with Titanium or Tantalum nonvolatile flash memory, they all have better retention storage property.