Dielectric properties and electrical conduction of high-k LaGdO3 ceramics

Abstract

The temperature and frequency dependent dielectric properties and leakage conduction mechanism in LaGdO3 (LGO) ceramics have been studied, and this material has been identified as a potential high-k candidate for the future complementary metal-oxide-semiconductor (CMOS) and dynamic random access memory (DRAM) technology nodes. The dielectric constant and the loss tangent at 100 kHz were ∼21.5 and ∼0.003, respectively, at ambient conditions without any significant temperature and voltage dependence. The ac conductivity shows the typical features of universal dynamic response (UDR) and obey the double power law σac=σdc+Aωn1+Bωn2 with three types of temperature dependent conduction processes involved; (i) a dc plateau (< 3 kHz) due to long range translational hopping, (ii) a mid frequency region due to the short range hopping (3–100 kHz), and (iii) a high frequency region due to localized or reorientational hopping (100–1000 kHz). The temperature dependent dc conductivity follows the Arrhenius relation with activation energies of 0.05 eV in the 200–400 K range and 0.92 eV in the 400–600 K range. The leakage current behavior reveals bulk limited Poole-Frenkel (PF) conduction mechanism and the estimated optical dielectric constant (ɛ∞) is 3.6.

Sintering characteristics and electrical properties of BaBi4Ti4O15 ferroelectric ceramics

“…In the temperature range (>T t ) the Arrhenius plots show a linear variation and the estimated activation energy values (Fig. 8) in the range E a = 1.04-1.16 eV are in agreement with earlier studies [39][40][41] and correspond to the migration of doubly ionized oxygen vacancies (Vö). In the Aurivillius family of oxides the major contribution to the electrical conductivity originates due to the loss of bismuth.…”

“…At higher temperatures (T P 150°C) variation in r ac (T) shows a frequency independent plateau in the low frequency range <1 kHz, whereas at higher frequencies (>1 kHz), r ac is frequency dependent with reduced dispersion. The observed frequency and temperature dependence in r ac could be fitted well to a double power law [40,45,46].…”

Advanced high-k dielectric amorphous LaGdO3 based high density metal-insulator-metal capacitors with sub-nanometer capacitance equivalent thickness

“…The equivalent breakdown field deduced from the slope of this plot was about $36 MV/cm which comes out to be $6 MV/cm [breakdown field, E BD ¼ equivalentfield=ðk=3:9Þ] by considering the permittivity of LGO (k $ 22). 10 This experimental value is comparable with the theoretical value obtained (5.5 MV/cm) by applying the "square root" rule in accordance with the thermo-chemical/molecular model 26 for the break down field E BD ¼ 29:9e À0:55 r . The maximum energy storage density calculated using the relation W ¼ ðe 0 e r E 2 BD =2Þ was around 40 J/cm 3 , and this higher figure may be of particular interest for energy density capacitor applications in energy storage and power compression devices.…”

Nonvolatile Resistive Memory Switching in Amorphous LaGdO3 Thin Films

“…We have recently shown that amorphous LaGdO 3 (LGO) a ternary high-k dielectric oxide material with high and linear dielectric constant of ~22, large band gap, good thermal stability, and high crystallization temperature of ~ 1000 °C is promising material for CMOS devices [3]. In this paper we report, to the best of our knowledge for the first time, the growth of RRAM devices based on amorphous thin films of LGO in Pt/ LGO/ Pt stack geometry, their unipolar resistive switching characteristics and associated conduction behaviors in both the low resistance state (LRS) and high resistance states (HRS).…”