Barrier height modification in Au/Ti/n-GaAs devices with a HfO2 interfacial layer formed by atomic layer deposition
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Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Indian Acad Sciences
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
X-ray photoelectron spectroscopy has been carried out to characterize the surface of the hafnia (HfO2) thin films grown on n-GaAs wafer by atomic layer deposition, and the surface morphology of the HfO2 layer on GaAs has been analysed using atomic force microscopy. The barrier height (BH) values of 1.03 and 0.93 eV (300 K) for the Au/Ti/HfO2/n-GaAs structures with 3- and 5-nm HfO2 interfacial layers, respectively, have been obtained from the I-V characteristics of the devices, which are higher than the value of 0.77 eV (300 K) for the Au/Ti/n-GaAs diode fabricated by us. Therefore, it can be said that the HfO2 thin layer at the metal/GaAs interface can also be used for BH modification as a gate insulator in GaAs metal-oxide semiconductor (MOS) capacitors and MOS field-effect transistors. The ideality factor values have been calculated as 1.028 and 2.72 eV at 400 and 60 K; and as 1.04 and 2.58 eV at 400 and 60 K for the metal-insulating layer-semiconductor (MIS) devices with 3- and 5-nm interfacial layers, respectively. The bias-dependent BH values have been calculated for the devices by both Norde's method and Gaussian distribution (GD) of BHs at each sample temperature. At 320 K, the phi b(V) value at 0.70 V for a 3-nm MIS diode is about 1.08 eV from the phi b(V)vs. V curve determined by the GD, and about 0.99 eV at 0.58 V for a 5-nm MIS diode. It has been seen that these bias-dependent BH values are in close agreement with those obtained by Norde's method for the same bias voltage values.
Açıklama
Anahtar Kelimeler
Barrier height modification and inhomogeneous, bias-dependent barrier height, metal-insulating layer-semiconductor (MIS) device, atomic layer deposition (ALD), temperature-dependent MIS diode parameters
Kaynak
Bulletin of Materials Science
WoS Q Değeri
Q3
Scopus Q Değeri
Q2
Cilt
42
Sayı
1
