Characterization of deep levels in Pt-GaN Schottky diodes depositedon intermediate-temperature buffer layers |
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Authors: | Leung B.H. Chan N.H. Fong W.K. Zhu C.F. Ng S.W. Lui H.F. Tong K.Y. Surya C. Lu L.W. Ge W.K. |
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Affiliation: | Dept. of Electron. & Inf. Eng., Hong Kong Polytech. Univ., Kowloon; |
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Abstract: | Gallium nitride (GaN)-based Schottky junctions were fabricated by RF-plasma-assisted molecular beam epitaxy (MBE). The GaN epitaxial layers were deposited on novel double buffer layers that consist of a conventional low-temperature buffer layer (LTBL) grown at 500°C and an intermediate-temperature buffer layer (ITBL) deposited at 690°C. Low-frequency excess noise and deep level transient Fourier spectroscopy (DLTFS) were measured from the devices. The results demonstrate a significant reduction in the density of deep levels in the devices fabricated with the GaN films grown with an ITBL. Compared to the control sample, which was grown with just a conventional LTBL, a three-order-of-magnitude reduction in the deep levels 0.4 eV below the conduction band minimum (Ec) is observed in the bulk of the thin films using DLTFS measurements |
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