Atomic-layer-deposited （ALD） Al2O3passivation dependent interface chemistry, band alignment and electrical properties of HfYO/Si gate stacks
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2019年第5期
论文作者：Shuang Liang Gang He Die Wang Fen Qiao
文章页码：769 - 776
摘 要：In this work, the effects of atomic-layer-deposited（ALD） Al2O3 passivation layers with different thicknesses on the interface chemistry and electrical properties of sputtering-derived HfYO gate dielectrics on Si substrates have been investigated. The results of electrical measurements and X-ray photoelectron sepectroscopy（XPS） showed that 1-nm-thick Al2O3 passivation layer is optimized to obtain excellent electrical and interfacial properties for HfYO/Si gate stack. Then, the metal-oxide-semiconductor capacitors with HfYO/1-nm Al2O3/Si/Al gate stack were fabricated and annealed at different temperatures in forming gas（95% N2+5% H2）. Capacitance-voltage（C-V） and current density-voltage（J-V） characteristics showed that the 250℃-annealed HYO high-k gate dielectric thin film demonstrated the lowest border trapped oxide charge density(-3.3 × 1010 cm-2), smallest gate-leakage current(2.45 × 10-6 A/cm2 at 2 V)compared with other samples. Moreover, the annealing temperature dependent leakage current conduction mechanism for Al/HfYO/Al2O3/Si/Al MOS capacitor has been investigated systematically. Detailed electrical measurements reveal that Poole-Frenkle emission is the main dominant emission in the region of low and medium electric fields while direct tunneling is dominant conduction mechanism at high electric fields.
Shuang Liang1，Gang He1,2，Die Wang1，Fen Qiao3
1. School of Physics and Materials Science, Radiation Detection Materials & Devices Lab, Anhui University2. Institute of Physical Science and Information Technology, Anhui University3. School of Energy & Power Engineering, Jiangsu University
摘 要：In this work, the effects of atomic-layer-deposited（ALD） Al2O3 passivation layers with different thicknesses on the interface chemistry and electrical properties of sputtering-derived HfYO gate dielectrics on Si substrates have been investigated. The results of electrical measurements and X-ray photoelectron sepectroscopy（XPS） showed that 1-nm-thick Al2O3 passivation layer is optimized to obtain excellent electrical and interfacial properties for HfYO/Si gate stack. Then, the metal-oxide-semiconductor capacitors with HfYO/1-nm Al2O3/Si/Al gate stack were fabricated and annealed at different temperatures in forming gas（95% N2+5% H2）. Capacitance-voltage（C-V） and current density-voltage（J-V） characteristics showed that the 250℃-annealed HYO high-k gate dielectric thin film demonstrated the lowest border trapped oxide charge density(-3.3 × 1010 cm-2), smallest gate-leakage current(2.45 × 10-6 A/cm2 at 2 V)compared with other samples. Moreover, the annealing temperature dependent leakage current conduction mechanism for Al/HfYO/Al2O3/Si/Al MOS capacitor has been investigated systematically. Detailed electrical measurements reveal that Poole-Frenkle emission is the main dominant emission in the region of low and medium electric fields while direct tunneling is dominant conduction mechanism at high electric fields.
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