Ultra-high thermal stability and extremely low D^sub it^ on HfO^sub 2^/p-GaAs(001) interface

• Published in: Microelectronic engineering Vol. 178; p. 154
• Main Authors: Wan, HW, Lin, YH, Lin, KY, Chang, TW, Cai, RF, Kwo, J, Hong, M
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier BV 25.06.2017
• Subjects: Current density; Gallium arsenide; Hafnium oxide; Leakage; Leakage current; Molecular beam epitaxy; Temperature; Thermal stability; Thick films; Thin films
• ISSN: 0167-9317; 1873-5568

Molecular beam epitaxy (MBE) HfO2 films ~ 1.5 nm thick were directly deposited on freshly grown GaAs(001)-4 × 6 reconstructed surfaces. The hetero-structure exhibits outstanding thermal stability up to 900 °C with excellent capacitance-voltage (C-V) and leakage current density-electric field (J-E) characteristics. We have extracted low interfacial trap densities (Dit's) with minimum value of 1.3 × 1011 eV-1 cm-2 from the measured quasi-static C-V (QSCV) characteristics. The smallest frequency dispersion of the C-Vs for the MBE-HfO2/p-GaAs(001) is ~ 5.2% at frequency range of 500 to 1 MHz and no trap-induced humps were observed in the C-Vs, as measured at 100 °C and 150 °C. Also, the leakage current density remains low of 10-8(A/cm2) at E < ± 3 (MV/cm). The key to passivate GaAs in attaining low Dit's and high-temperature thermal stability is to ensure the cleanness of GaAs surface prior to the high-κ deposition.