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

Effects of post-deposition annealing ambient on Y2O3 gate deposited on silicon by RF magnetron sputtering

“…Further scaling of SiO 2 will result in exceptionally high direct tunneling current and increase reliability issue [3][4][5]. Thus, numerous investigations have been performed to substitute the SiO 2 with high dielectric constant (k) materials, such as HfO 2 [6][7][8], Al 2 O 3 [9], ZrO 2 [10,11], CeO 2 [12], Er 2 O 3 [13,14], and Y 2 O 3 [4,. Of these high-k oxides, Y 2 O 3 is considered as one of the potential candidates for substituting SiO 2 due to its fascinating properties, such as large band gap (∼5.5 eV), large conduction band offset (∼2.3 eV), high-k value (k = 15-18), low lattice mismatch and good thermal stability with silicon [4,[15][16][17][18][19].…”

Low-Energy Path to Dense HfO2 Thin Films with Aqueous Precursor

“…Thin film HfO 2 deposition through conventional sol−gel routes via spin coating or dip coating has been described in several reports. For example, hafnia sol precursors have been made by mixing HfCl 4 into ethanol or 1-methoxy-2-propanol followed by hydrolysis and peptization with acid. − Similar colloidal suspensions have been produced by using HfOCl 2 as the starting material . Precursors have also been prepared by stabilizing hafnium ethoxide or hafnium pentadionate in acetylacetone/ethanol. − Each of these methods has relied on the preparation of large sol particles or use of a metal−organic reagent.…”

“…Even though high-temperature annealing may facilitate densification of the deposited sols, it also leads to HfO 2 crystallization and grain boundary formation as annealing temperatures reach 500 °C. As insulators, these films exhibit high leakage current densities near 10 −5 A/cm 2 at 1 MV/cm, , 3 orders of magnitude higher than that required for a thin film transistor (TFT) gate dielectric. To produce higher-quality material, a presumed surface sol−gel method has been described, which involves the use of a precursor of hafnium n -butoxide dissolved in toluene/ethanol .…”

Metal-oxide-semiconductor characteristics of lanthanum cerium oxide film on Si

“…The acquisition of the highest V B at 1000°C might be due to the formation of SiO x and silicates IL. It had been reported that IL would reduce the dielectric polarization between the high-k gate oxide and substrate, thus reducing the phonon scattering effect [48]. These benefits had led to a lower leakage current and a higher V B in MOS structures utilizing CeO 2 /Ce 2 Si 2 O 7 , HfO 2 /Hf silicate, and ZrO 2 /Zr silicate [18,50,51].…”

“…The oxide annealed at the highest temperature showed the highest dielectric breakdown voltage (V B ), followed by the oxide annealed at 800°C, 600°C, and the lowest V B was demonstrated by the oxide annealed at the lowest temperature. V B is defined as an instantaneous increase in leakage current density at a specific gate voltage in which the oxide experiences an electrical breakdown [48,49]. The acquisition of the highest V B at 1000°C might be due to the formation of SiO x and silicates IL.…”