Fixed charge and trap states of in situ Al2O3 on Ga-face GaN metal-oxide-semiconductor capacitors grown by metalorganic chemical vapor deposition

Abstract

Articles you may be interested inNitride passivation reduces interfacial traps in atomic-layer-deposited Al2O3/GaAs (001) metal-oxidesemiconductor capacitors using atmospheric metal-organic chemical vapor deposition Appl. Phys. Lett. 105, 033513 (2014); 10.1063/1.4891431 In-situ metalorganic chemical vapor deposition and capacitance-voltage characterizations of Al2O3 on Ga-face GaN metal-oxide-semiconductor capacitors Appl. Phys. Lett. 103, 053509 (2013); 10.1063/1.4817385Bulk and interface trapping in the gate dielectric of GaN based metal-oxide-semiconductor high-electron-mobility transistors Appl.Two-dimensional electron gases in Ga-face and N-face AlGaN/GaN heterostructures grown by plasma-induced molecular beam epitaxy and metalorganic chemical vapor deposition on sapphireIn situ Al 2 O 3 on Ga-face GaN metal-oxide-semiconductor capacitors (MOSCAPs) were grown by metalorganic chemical vapor deposition and measured using capacitance-voltage techniques. The flat band voltage and hysteresis had a linear relationship with Al 2 O 3 thickness, which indicates the presence of fixed charge and trap states that are located at or near the Al 2 O 3 /GaN interface. In addition, slow and fast near-interface states are distinguished according to their different electron emission characteristics. Atom probe tomography was used to characterize the in situ MOSCAPs to provide information on the Al/O stoichiometric ratios, Al 2 O 3 /GaN interface abruptnesses, and C concentrations. The in situ MOSCAPs with Al 2 O 3 deposited at 700 C exhibited an order of magnitude higher fast near-interface states density but a lower slow near-interface states density compared with those with Al 2 O 3 deposited at 900 and 1000 C. Furthermore, the 700 C MOSCAPs exhibited a net negative fixed near-interface charge, whereas the 900 and 1000 C MOSCAPs exhibited net positive fixed near-interface charges. The possible origins of various fixed charge and trap states are discussed in accordance with the experimental data and recently reported first-principals calculations. V C 2013 AIP Publishing LLC. [http://dx.

On the origin of interface states at oxide/III-nitride heterojunction interfaces

“…Choi et al 35 using the first principles calculations showed that C Al can produce traps near/at the Al 2 O 3 /III-nitride interface. Based on these results as well as on the comparative electrical and photoelectric studies, Liu et al 36 suggested that the slow interface states at Al 2 O 3 /GaN interfaces originate from C impurities. Furthermore, Jackson et al 37 using the capacitance deep level optical spectroscopy claimed that D it (E) near VB at Al 2 O 3 /GaN interface is due to residual C atoms from nucleation of the ALD process.…”

“…According to some reports, [35][36][37] the origin of interface states at oxide/III-N interfaces can be related to C impurities near/at the interface. Choi et al 35 using the first principles calculations showed that C Al can produce traps near/at the Al 2 O 3 /III-nitride interface.…”

Role of ZrO2 Passivation Layer Thickness in the Fabrication of High‐Responsivity GaN Ultraviolet Photodetectors

“…The value of Q trapped extracted from Δ V FB is found to be 5.1 ± 0.4 × 10 10 cm −2 in all the samples. Note that V FB exhibits a linear relationship with ZrO 2 layer thickness, which along with a constant value of Q trapped provides further evidence that the trapped charge is primarily localized as a line charge (in units of cm −2 ) at or near the ZrO 2 /GaN interface . The aforementioned results confirm that no new slow trap states are generated at a large thickness of the ZrO 2 layer.…”

Low-temperature atomic layer deposition-grown Al2O3 gate dielectric for GaN/AlGaN/GaN MOS HEMTs: Impact of deposition conditions on interface state density

“…Note that for fully compensated surface polarization charge by N DS , the net charge N int tends to be close to zero. [7][8][9]14 D it distribution was determined on MOS-HEMT structures with t ox ¼ 10 nm only, as it is expected to be independent of t ox . Two complementary techniques were used: (1) D it in the energy range of E C -E ¼ 0.5-1.0 eV was determined using V th -transients, deduced from the capacitance transients measured at V g %V th À0.5 V at temperatures of 25, 75, and 125 C. Only relative change (DV th ) between V th transients measured after "filling" pulse V F ¼ 0 (no filling) and V F ¼ 1.5 V (interface traps filling) was used for D it determination, to cancel out possible bulk trapping process (i.e., V th drift) previously discussed in Ref.…”