Effect of H2O evolving from TEOS based SiO2 film on the EEPROM cell characteristic

• Published in: Microelectronic engineering Vol. 83; no. 10; pp. 2001 - 2003
• Main Authors: LEE, Junghwan, CHUNG, Eunyoung, MOON, Won, DONG HACK SUH
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 01.10.2006
• Subjects: Applied sciences; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Integrated circuits; Integrated circuits by function (including memories and processors); Microelectronic fabrication (materials and surfaces technology); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors; Voltage threshold; Heat treatment; Fourier transformation; Cell Vt; Transistor; Chemical vapor deposition; EEPROM; Microelectronic fabrication; EEPROM memory; High voltage; Low pressure; Integrated circuit; Leakage current; SiO2
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2006.03.003

In this paper, we investigate the effect of water (H2O) molecules evolving from silicon dioxide (SiO2) film deposited by low pressure chemical vapor deposition (LPCVD) at 670 deg C on the transistor characteristic of an electrically erasable programmable read only memory (EEPROM) cell. Fourier Transform Infra red (FT-IR) analysis reveals that H2O is captured during film deposition and diffused to silicon surface during high thermal processing. The diffused H2O molecules lower threshold voltage (Vt) of cell transistor and, thus, leakage current of the cell transistor is increased. In erased cell, Vt lowering is 0.25V in which it increases leakage current of cell transistor from 1 to 100pA. This results in the lowering of high voltage margin of a 512Kb EEPROM from 2.8 to 2.6V at 85 deg C.