Detail publikace

Niobium Oxide and Tantalum Capacitors: Leakage Current and M-I-S Model Parameters

Originální název

Niobium Oxide and Tantalum Capacitors: Leakage Current and M-I-S Model Parameters

Anglický název

Niobium Oxide and Tantalum Capacitors: Leakage Current and M-I-S Model Parameters

Jazyk

en

Originální abstrakt

The method for quality and reliability of NbO and Ta capacitors is based on assessment of defects in insulating layer. The model of the MIS structure is used to give a physical interpretation of the NbO and Ta capacitors VA and CV characteristics and theirs temperature dependences. The MIS structure consists from metallic NbO or Ta, insulating layer made from Nb2O5 or Ta2O5 and semiconductor - MnO2. For the capacitor polarized in the "normal mode", (with the NbO and Ta electrode positive), ohmic, Poole-Frenkel and tunneling are the dominant conduction mechanisms. Insulating layer thickness in these devices has 20 to 100 nm and then these devices belong to nanoscale electronic devices in which quantum effects play important role. Insulating layer is not perfect structure and it contains oxygen vacancies and the other defects. They create deep localized states acting as donors with concentration about 1018 to 1019 cm-3. At such value of donor concentration impurity band can be created. Electron transport is realized by Ohmic and Poole-Frenkel conductivity. The activation energy for this impurity conductivity is about 0.4 eV. The theoretical barrier hight for electron transport in normal mode is given by the difference between Ta/NbO and MnO2 work funtions. In these cases the potential barriers are about 1.5 eV. This value is changed if the traps are present at the Nb2O5 - MnO2 or Ta2O5 - MnO2 interfaces. We have three methods how to determine this barrier high: The VA characteristics in reverse mode at T = 300 K The The tunnelling current transport in normal and reverse mode at T = 80 K CV characteristics

Anglický abstrakt

The method for quality and reliability of NbO and Ta capacitors is based on assessment of defects in insulating layer. The model of the MIS structure is used to give a physical interpretation of the NbO and Ta capacitors VA and CV characteristics and theirs temperature dependences. The MIS structure consists from metallic NbO or Ta, insulating layer made from Nb2O5 or Ta2O5 and semiconductor - MnO2. For the capacitor polarized in the "normal mode", (with the NbO and Ta electrode positive), ohmic, Poole-Frenkel and tunneling are the dominant conduction mechanisms. Insulating layer thickness in these devices has 20 to 100 nm and then these devices belong to nanoscale electronic devices in which quantum effects play important role. Insulating layer is not perfect structure and it contains oxygen vacancies and the other defects. They create deep localized states acting as donors with concentration about 1018 to 1019 cm-3. At such value of donor concentration impurity band can be created. Electron transport is realized by Ohmic and Poole-Frenkel conductivity. The activation energy for this impurity conductivity is about 0.4 eV. The theoretical barrier hight for electron transport in normal mode is given by the difference between Ta/NbO and MnO2 work funtions. In these cases the potential barriers are about 1.5 eV. This value is changed if the traps are present at the Nb2O5 - MnO2 or Ta2O5 - MnO2 interfaces. We have three methods how to determine this barrier high: The VA characteristics in reverse mode at T = 300 K The The tunnelling current transport in normal and reverse mode at T = 80 K CV characteristics

BibTex


@inproceedings{BUT27973,
  author="Josef {Šikula} and Vlasta {Sedláková} and Hana {Navarová} and Jan {Hlávka} and Munecazu {Tacano} and Zdeněk {Sita}",
  title="Niobium Oxide and Tantalum Capacitors: Leakage Current and M-I-S Model Parameters",
  annote="The method for quality and reliability of NbO and Ta capacitors is based on assessment of defects in insulating layer. The model of the MIS structure is used to give a physical interpretation of the NbO and Ta capacitors VA and CV characteristics and theirs temperature dependences. The MIS structure consists from metallic NbO or Ta, insulating layer made from Nb2O5 or Ta2O5 and semiconductor - MnO2. For the capacitor polarized in the "normal mode", (with the NbO and Ta electrode positive), ohmic, Poole-Frenkel and tunneling are the dominant conduction mechanisms. Insulating layer thickness in these devices has 20 to 100 nm and then these devices belong to nanoscale electronic devices in which quantum effects play important role. Insulating layer is not perfect structure and it contains oxygen vacancies and the other defects. They create deep localized states acting as donors with concentration about 1018 to 1019 cm-3. At such value of donor concentration impurity band can be created. Electron transport is realized by Ohmic and Poole-Frenkel conductivity. The activation energy for this impurity conductivity is about 0.4 eV. The theoretical barrier hight for electron transport in normal mode is given by the difference between Ta/NbO and MnO2 work funtions. In these cases the potential barriers are about 1.5 eV. This value is changed if the traps are present at the Nb2O5 - MnO2 or Ta2O5 - MnO2 interfaces. We have three methods how to determine this barrier high: 
The VA characteristics in reverse mode at T = 300 K
The The tunnelling current transport in normal and reverse mode at  T = 80 K 
CV characteristics",
  address="Electronic Components, Assemblies&Materials Association",
  booktitle="Proceedings of CARTS USA 2007",
  chapter="27973",
  institution="Electronic Components, Assemblies&Materials Association",
  year="2007",
  month="january",
  pages="337--345",
  publisher="Electronic Components, Assemblies&Materials Association",
  type="conference paper"
}