Low Temperature Deposition of HfO₂ Gate Insulator on SiC by Metalorganic Chemical Vapor Deposition

Abstract

Low temperature deposition of HfO2 films on 4H-SiC(0001) substrates by pulse introduced metalorganic chemical vapor deposition (MOCVD) using tetrakis-diethylamido-hafnium [Hf[N(C2H5)2]4, (TDEAH)] and H2O has been investigated. HfO2 films with relatively low leakage current density of 10-4 A/cm2 were obtained even at a deposition temperature as low as 190 °C. We demonstrate that the HfO2/SiC interface, where the HfO2 was deposited at 190 °C, has lower interface state density than a typical thermally-grown SiO2/SiC interface. It is also shown by X-ray photoelectron spectroscopy (XPS) that the HfO2/SiC structure fabricated at 190 °C has lower SiOx count than the HfO2/SiC structure fabricated at 400 °C.

Anomalously High Channel Mobility in SiC-MOSFETs with Al₂O₃/SiO_x/SiC Gate Structure

“…We observe clear deposition temperature dependence. We have previously characterized HfO 2 /SiC interface properties and have reported that SiC can be oxidized during the oxide deposition even at low temperature of 400 o C which degrade HfO 2 /SiC electrical properties [7]. Hence, it can be considered that the low temperature deposition of Al 2 O 3 effectively suppressed the oxidation of SiC substrate and resulted in a good interface property.…”

Investigation of sol–gel derived HfO2 on 4H-SiC

“…Up to date, all of the reported techniques were purely concentrated on methods such as metalorganic chemical vapor deposition, atomic layer deposition (ALD), pulsed laser deposition (PLD), and others, except for sol-gel method [7][8][9]. In contrast, sol-gel technique has been employed to deposit HfO 2 film on Si [10,11] due to its relatively low cost and simple deposition technique.…”

Effect of Oxidant in MOCVD-Growth of Al₂O₃ Gate Insulator on 4H-SiC MOSFET Properties

“…Therefore, to avoid the formation of interface states, many attempts to use a deposited oxide as a gate insulator of the SiC MOS devices were reported [1,2]. We have previously reported excellent performance in 4H-SiC MOSFETs with Al 2 O 3 gate insulator which was deposited at as low as 190 o C by metal-organic chemical vapor deposition (MOCVD) [3][4][5][6] . In the previous work, we used triethyl-aluminum (TEA) and H 2 O as precursors and demonstrated that the peak value of field-effect-mobility was approximately 60 cm 2 /Vs when the Al 2 O 3 gate insulator was deposited on HF-treated 4H-SiC (0001) substrate with TEA and H 2 O at 190 o C [3].…”