Comprehensive study on M-I-S contact system and its application to n-InGaAs semiconductor substrate
Date Issued
2015
Date
2015
Author(s)
Lien, Chin
Abstract
In this paper, we make a comprehensive study on Metal-Insulator-Semiconductor (M-I-S) contact system for III-V compound material, InGaAs. With the scaling limitation of Si-based device, III-V compound materials are regarded as the promising candidates for n-channel device in next generation because of its high electron mobility and low electron effective mass. However, III-V compound materials also have the same problem as Si or Ge, the Fermi Level Pinning (FLP). Recently, the Metal-Insulator-Semiconductor (M-I-S) contact structures have been proposed to release the Fermi Level Pinning (FLP), by modulating the Schottky Barrier Height (SBH) and futher reduce the contact resistivity. Reduction of contact resistivity plays an important role on boosting the device performance, especially in on-state current, in scaling generation. At the first part, I collect several literatures about recent M-I-S development and list some papers which focus on M-I-S contact system based on different semiconductor substrates i.e. Si, Ge and III-V compound material. Then the mechanisms of Fermi Level Pinning and M-I-S contact system are also given. The key points of reduction of contact resistivity using M-I-S system are the properties of inserting insulator i.e. dielectric constant, band offset, carrier effective mass and band gap as well as the interactions between insulator and substrate. At the second part, I use three different kinds of insulator: BaTiO3, TiO2 and ZnO on InGaAs substrate. Then Ti is used as contact metal to form M-I-S ohmic contact. The experimental results of M-S and M-I-S contact were discussed here. We find that the contact resistivity will reduce ~10x when we insert ZnO as insulator. Due to its nearly zero conduction band offset, the reduction of contact resistivity is still achieved even though its dielectric constant is not high compare to other two insulators.
Subjects
InGaAs
contact resistivity
Schottky Barrier Height
Fermi Level Pinning
Metal-Insulator-Semiconductor contact system
Type
thesis
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