TY - GEN
T1 - The effect of metallic impurities on the dielectric breakdown of oxides and some new ways of avoiding them
AU - Verhaverbeke, S.
AU - Meuris, M.
AU - Mertens, P. W.
AU - Heyns, M. M.
AU - Philipossian, Ara
AU - Graf, D.
AU - Schnegg, A.
N1 - Publisher Copyright:
© 1991 IEEE.
PY - 1991
Y1 - 1991
N2 - The effect of metallic contamination on the dielectric breakdown of thermal oxide layers is investigated. Wafers were intentionally contaminated with Ca, Zn, Fe, Cu or Al. The oxidation behavior of the contaminants and their effect on the Si surface roughness were investigated and correlated with the oxide breakdown properties. It was observed that Ca interacts strongly with the Si substrate during ramp-up. This results in a large increase in the Si surface roughness and poor breakdown properties of the thermal oxide layer. Fe degrades the oxide integrity by the formation of defect spots during the oxidation and Al induces damage under the SiO2/poly-Si interface. Metals such as Cu and Zn diffuse easily in the Si substrate and, consequently, do not have a large impact on the oxide quality. Standard grade chemicals are the main source for the metallic impurities. After switching to ultrapure chemicals, the DI-water distribution system becomes the limiting factor. Some techniques to reduce the contamination and Si-surface roughening are presented.
AB - The effect of metallic contamination on the dielectric breakdown of thermal oxide layers is investigated. Wafers were intentionally contaminated with Ca, Zn, Fe, Cu or Al. The oxidation behavior of the contaminants and their effect on the Si surface roughness were investigated and correlated with the oxide breakdown properties. It was observed that Ca interacts strongly with the Si substrate during ramp-up. This results in a large increase in the Si surface roughness and poor breakdown properties of the thermal oxide layer. Fe degrades the oxide integrity by the formation of defect spots during the oxidation and Al induces damage under the SiO2/poly-Si interface. Metals such as Cu and Zn diffuse easily in the Si substrate and, consequently, do not have a large impact on the oxide quality. Standard grade chemicals are the main source for the metallic impurities. After switching to ultrapure chemicals, the DI-water distribution system becomes the limiting factor. Some techniques to reduce the contamination and Si-surface roughening are presented.
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U2 - 10.1109/IEDM.1991.235421
DO - 10.1109/IEDM.1991.235421
M3 - Conference contribution
AN - SCOPUS:84954092004
T3 - Technical Digest - International Electron Devices Meeting, IEDM
SP - 71
EP - 74
BT - International Electron Devices Meeting 1991, IEDM 1991
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - International Electron Devices Meeting, IEDM 1991
Y2 - 8 December 1991 through 11 December 1991
ER -