Enhancement of electrical characteristics and reliability in crystallized ZrO2 gate dielectrics treated with in-situ atomic layer doping of nitrogen

• Published in: Applied surface science Vol. 305; pp. 214 - 220
• Main Authors: Huang, Jhih-Jie, Huang, Li-Tien, Tsai, Meng-Chen, Lee, Min-Hung, Chen, Miin-Jang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.06.2014; Elsevier
• Subjects: Atomic layer deposition; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; High-K gate dielectrics; In-situ atomic layer doping; Physics; Remote plasma; Zirconium oxide; High-K gate dielectrics; Remote plasma; Zirconium oxide; Atomic layer deposition; In-situ atomic layer doping; Inorganic compounds; In situ; Transition element compounds; Nitrogen; Reliability
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2014.03.039

•The remote plasma in-situ atomic layer doping technique under the N2 and NH3 atmospheres was used to incorporate nitrogen into the crystallized ZrO2 gate dielectrics.•The removal of nitrogen from ZrO2 at relatively low temperature of 450°C implies that the formation of nitrogen bonding using the remote plasma is not thermally stable in nature due to the low deposition temperature.•The decrease in CET may be attributed to the increment of dielectric constant in the ZrO2 layer due to the formation of Zr–N bonding as a result of the nitrogen incorporation.•The Jg was reduced up to two orders of magnitude by the incorporation of the nitrogen because of the deactivation of the oxygen vacancies. The Dit was also suppressed due to the passivation of the interfacial states by hydrogen provided by the remote NH3 plasma.•The interface between the high-K gate dielectrics and Si was probed by the PL spectroscopy, revealing that the hydrogen passivation caused by the remote NH3 plasma treatment is highly correlated with the PL intensity and Dit. The crystallized ZrO2 high-K gate dielectrics treated with in-situ atomic layer doping of nitrogen using remote N2 and NH3 plasma were investigated, to suppress the capacitance equivalent thickness (CET), leakage current density (Jg), and interfacial state density (Dit). The stress-induced leakage current (SILC) was reduced significantly as well. The tetragonal/cubic phase of ZrO2 was formed by post metallization annealing at a low temperature of 450°C to offer a high dielectric constant of the gate oxide. The in-situ atomic layer doping of nitrogen using the remote NH3 plasma contributes to the deactivation of the oxygen vacancies and the well passivation of Dit. Accordingly, a suppressed Jg of 4.79×10−5Acm−2 and Dit of 3.96×1011cm−2eV−1 were realized in the crystallized ZrO2 gate oxide with a low CET of 1.35nm. The gate dielectrics were also optically examined by the photoluminescence from the high-K/Si interface, indicating that the Dit is highly correlated with the hydrogen passivation originating from the remote NH3 plasma. The results indicate that in-situ atomic layer doping of nitrogen is an applicable and effective technique to improve the electrical properties of crystallized gate dielectrics in the advanced metal-oxide-semiconductor devices.