Optical Charge Pumping Method for Extracting the Energy Level of Interface States in a Program/Erase Cycled SONOS Flash Memory Cell and Its Program Time Dependence

Abstract

Optical Charge Pumping Method for Extracting the Energy Level of Interface States in a Program/Erase Cycled SONOS Flash Memory Cell and Its Program Time Dependence Kichan Jeon, Sunyeong Lee, Jun-Hyun Park, Changmin Choi, Kwan-Jae Song, So Ra Park, Tae Woon Kim, Ji Eun Lee, Sungwook Park, Sangwon Lee, Jaeman Jang, Dae Hwan Kim and Dong Myong Kim School of Electrical Engineering, Kookmin University, Seoul 136-702 (Received 20 February 2008) The optical charge pumping (CP) technique is proposed as a simple and fast method for extracting the energy distribution of the interface trap, Dit, of silicon-oxide-nitride-oxide-silicon (SONOS) ash memories. It is based on the subthreshold slope change induced by optically excited traps and interface states in SONOS memory cell transistors under sub-bandgap photonic illumination. This technique is advantageous for characterizing charge traps in nano-scale emerging devices. The technique has been applied to SONOS charge-trapping ash memories and the generation and the passivation of interface traps are investigated as a function of both the number of program/erase cycles and the program time. PACS numbers: 85.30.De, 85.30.Tv