Effect of HfxZr1−xO2/Ge metal–ferroelectrics–insulator–semiconductor interfaces on polarization reversal behavior

• Published in: Japanese Journal of Applied Physics Vol. 62; no. SC; p. SC1093
• Main Authors: Iwashige, Koichiro, Toprasertpong, Kasidit, Takenaka, Mitsuru, Takagi, Shinichi
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese Journal of Applied Physics 01.04.2023
• Subjects: Capacitors; Depletion; Electric fields; Evaluation; Ferroelectric materials; Ferroelectricity; Field effect transistors; Germanium; Impurities; Interfacial properties; Polarization characteristics; Semiconductor devices; Substrates; Voltage drop
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/acb829

To evaluate the polarization characteristics of ferroelectric-gate field-effect transistors, metal–ferroelectrics–insulator–semiconductor (MFIS) structures are often used. This study examines the influence of interface characteristics on polarization characterization in MFIS on low-impurity-concentration substrates by experimentally evaluating the ferroelectric properties of HfxZr1−xO2 (HZO)/Ge MFIS capacitors with different interface properties. Usually, polarization reversal behavior is not observed for MFIS capacitors on low-impurity-concentration substrates. However, it is found that, when the interface properties are poor and the interface state density is high, polarization reversal behavior can be observed even on the low-impurity concentration substrates. In lightly-doped MFIS capacitors with many interface states, the response of the interface states at low measurement frequencies suppresses the depletion layer change and voltage drop in the Ge substrate, resulting in the high electric field across the HZO films and observation of polarization reversal behavior.