Investigation of Electrical and Interfacial Chemistry Analyses for Atomic-Layer-Deposition ZrO2/Al2O3/In0.53Ga0.47As MOSCAPs

Autor: Chang, Pang-Sheng, 張邦聖
Rok vydání: 2013
Druh dokumentu: 學位論文 ; thesis
Popis: 102
In the beginning of this thesis, we have investigated the surface pretreatment before depositing gate dielectric by using the precursors of ALD system, such as TMA and TEMAZ. However, compared to TEMAZ, we find the TMA surface treatment is effective to suppress the frequency dispersion and interface states in accumulation and depletion region. In order to further discuss the interface and gate oxide property of ZrO2/In0.53Ga0.47As MOSCAPs, we apply various post-deposition annealing temperatures with forming gas annealing (FGA). Moreover, by TMA pretreatment, we incorporate several Al2O3 inter-layers with the interface of ZrO2 and In0.53Ga0.47As and discuss their interface properties. It is noted that the MOSCAPs under PDA 300 °C with FGA show the best electrical characteristics at each Al2O3 inter-layer conditions. In addition, we utilize the conductance method to extract the density of interface states and still observe that the Dit exists near midgap is the lowest at PDA 300 °C with FGA. With the evidence of XPS analysis, we suppose that the result might be caused by higher amounts of the As2+/As2O5, As2O3/As2O5, and In2O3/InAsO4 at the MOSCAPs interface. Furthermore, from the electrical and interfacial chemistry characteristics, we demonstrate that the interface quality could be improved with thicker Al2O3 inter-layer. Eventually, we establish a distributed model to explain the tunneling mechanism between the semiconductor surface and trap states in the gate oxide which is biased in accumulation region. And we fit the experimental data with the model and quantitatively extract trap states density of the gate dielectric. As comparing with the aforementioned results, they are in good consistency.
Databáze: Networked Digital Library of Theses & Dissertations
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