Characteristics of Stacked HfON and HfZrO2 Ferroelectric Films and Its Application on Junctionless FET

Autor: LIN, TAI-YIN, 林岱瑩
Rok vydání: 2019
Druh dokumentu: 學位論文 ; thesis
Popis: 107
This thesis mainly studies the characteristics of HfZrO2 film and stacked HfON/HfZrO2 film in metal/ferroelectric film/interfacial layer (IL)/Si substrate (MFIS) capacitance structure and its application on the nanowire junctionless field effect transistor. Firstly, four types of dielectric films of HfZrO2, HfON, HfZrO2/HfON and HfON/HfZrO2 are studied. According to the experimental results, the HfON/HfZrO2 structure reveals the best polarization value. In addition, the effects of different thicknesses of HfON film (1, 2 and 3 nm) stacked on the HfZrO2 are also investigated. The stack dielectrics are HfON (1 nm)/HfZrO2 (6 nm), HfON (2 nm)/HfZrO2 (5 nm) and HfON (3.5 nm)/HfZrO2 (3.5 nm). From the experiment results, the characteristics of polarization value of the HfON (2 nm)/HfZrO2 (5 nm) shows the best one. Among the thermal annealing conditions, the microwave annealing (MWA) method is better than that of the RTA. After the MWA results of the above experiments, the best MWA condition is at 2400W/200s. In reliability testing, the HfON(2 nm)/HfZrO2(5 nm) of MFIS structure presents the best reliability. Therefore, the stack gate dielectric is also applied in the nanowire junctionless FET (JL-FET). In compared with HfZrO2 and HfON/HfZrO2 as the gate dielectrics of the JL-FETs, the JL-FET with HfON(2 nm)/HfZrO2(5 nm) gate dielectric shows the better ION/IOFF ratio and the subthreshold swing (S.S.). The better performance of JL-FET is the S.S = 61.33 mV/dec when Wch/Lch=60/120 (nm), and the leakage current is small, DIBL is 15.66 mV/V. On the other hand, when device dimension is Wch/Lch=60/200 (nm), the S.S is 64.79 mV/dec and the DIBL is 56.42 mV/V. Finally, the nanowire JL-FET with HfON (2 nm)/HfZrO2 (5 nm) gate dielectric presents the better ION/IOFF ratio and S.S. performance. But the ION current is lower, presumably, the contact metal filling is not very well, resulting in the larger contact resistance and the lower ON current.
Databáze: Networked Digital Library of Theses & Dissertations
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