Study of Metal-Oxide-Semiconductor Capacitors with Nitrided Hafnium Oxide Gate Dielectrics Grown by Atomic Layer Deposition
Date Issued
2014
Date
2014
Author(s)
Kao, Tung-Yi
Abstract
In the thesis, hafnium oxides (HfO2) gate dielectrics were deposited by thermal mode atomic layer deposition (ALD) and remote plasma atomic layer deposition (RPALD) as the gate dielectrics in metal-oxide-semiconductor (MOS) devices. The experimental result reveals that the electrical properties of HfO2 gate dielectrics prepared by RPALD is superior to that deposited by thermal mode ALD. The effect of nitridation treatment on the electrical properties of HfO2 gate dielectrics was further investigated, in which the nitridation treatments were performed on the top (TN) and bottom (BN) region of the HfO2 gate dielectrics, respectively. As compared with the TN samples, the BN samples exhibit a superior electrical properties, probably due to the suppressed interfacial layer.The capacitance equivalent thickness (CET) of 1.3nm and an effective dielectric constant of 16.48 was achieved in the BN samples. In addition, because the progress of FinFET is of major interest, the same experiments were also carried out on Si(110) substrate. Similar results were also obtained: the electrical properties of the BN samples are also better than those of the TN samples, with a low CET of 1.33 nm and an effective dielectric constant of 16.45 Finally, hafnium zirconium oxides (HfZrO) with different ratios of Hf:Zr were prepared by RPALD. The tetragonal crystalline phase was observed after the post-deposition annealing with an increase of the Zr composition. Thus the dielectric constant was enhanced but the leakage current density increased due to the crystalline gate dielectrics. Therefore, a further nitridation treatment was performed to suppress the leakage current density. As a result, a low CET of 1.2nm, a high effective dielectric constant of 20.22, and a low leakage current density of 4.0x10-4A/cm2 was reached in the HfZrO gate dielectrics.
Subjects
原子層沉積技術
遠程電漿輔助原子層沉積技術
二氧化鉿
氧化鋯鉿
金屬氧化物半導體
高介電係數閘極介電層
氨氣電漿處理
Type
thesis
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