Defects-induced gap states in hydrogenated γ-alumina used as blocking layer for non-volatile memories

• Published in: Microelectronic engineering Vol. 88; no. 7; pp. 1448 - 1451
• Main Authors: Masoero, L., Blaise, P., Molas, G., Colonna, J.P., Gély, M., Barnes, J.P., Ghibaudo, G., De Salvo, B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-07-2011; Elsevier
• Subjects: Al 2O 3; Alumina; Applied sciences; Atomistic simulation; Defects; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; Flash memories; High-k; Integrated circuits; Integrated circuits by function (including memories and processors); Interpoly dielectrics; Non-volatile memories; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; TANOS; Interpoly dielectrics; High-k; Atomistic simulation; TANOS; Flash memories; Alumina; Non-volatile memories; Al 2O 3; Defects; Tantalum nitride; TANOS structure; Tunnel effect; Blocking layer; Al; IV-VI compound; O; Energy gap; Electronic conduction; Interpoly dielectric; III-VI compound; Non volatile memory; Defect; Defect states; Silicon nitride; Retention factor; Charge carrier trapping; Atomistic model; Flash memory; Silicon oxides; Integrated circuit; Leakage current; High k dielectric; Miniaturization
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2011.03.029

In this work we used atomistic simulation to simulate a 160-atoms supercell of γ-Al
2O
3 with various potential defects. For each defect we computed the formation energy and the density of state in order to find the stable and electrically active defects in γ-alumina.
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► Alumina used as a blocking layer for non-volatile memories. ► Electronic conduction through alumina layer is one of the fundamental limits for the downscaling of TANOS (TaN–Al
2O
3–Si
3N
4–SiO
2–Si) devices. ► Leakage current through Al
2O
3 that affects the memory retention characteristic is probably related to some trap assisted tunnelling. ► We used atomistic calculations to compute the Gibb’s energy and the DOS of a set of defects in γ-Al
2O
3. ► We found potential defects that are stable and could induce electronic levels inside the band gap of alumina.
Electronic conduction through alumina used as a blocking layer for non-volatile memories is one of the fundamental limits for the downscaling of TANOS (TaN–Al
2O
3–Si
3N
4–SiO
2–Si) devices. Especially, it has been shown that the leakage current through Al
2O
3 that affects the memory retention characteristic is probably related to some trap assisted tunnelling. In this work we use atomistic calculations to find potential defects that could induce electronic levels inside the band gap of alumina.