Excellent frequency dispersion of thin gadolinium oxide high-k gate dielectrics

Abstract

In this letter, we reported a high-k gadolinium oxide (Gd2O3) gate dielectric formed by reactive rf sputtering. It is found that the Gd2O3 gate dielectric film exhibits excellent electrical properties such as low leakage current density, high breakdown voltage, and almost no hysteresis and frequency dispersion in C-V curves comparable to that of HfO2 film. This indicates that postprocessing treatments can reduce a large amount of interface trap and can passivate a large amount of trapped charge at defect sites.

Dielectric relaxation of high-k oxides

“…Among them are cerium oxide CeO 2 [16-23], cerium zirconate CeZrO 4 [24], gadolinium oxide Gd 2 O 3 [25-27], erbium oxide Er 2 O 3 [28,29], neodymium oxide Nd 2 O 3 [30,31], aluminum oxide Al 2 O 3 [32,33], lanthanum aluminum oxide LaAlO 3 [34,35], lanthanum oxide La 2 O 3 [36], yttrium oxide Y 2 O 3 [37], tantalum pentoxide Ta 2 O 5 [38], titanium dioxide TiO 2 [39], zirconium dioxide ZrO 2 [40,41], lanthanum-doped zirconium oxide La x Zr 1 −x O 2 −δ [42,43], hafnium oxide HfO 2 [44], HfO 2 -based oxides La 2 Hf 2 O 7 [45], Ce x Hf 1-x O 2 [46], hafnium silicate HfSi x O y [47], and rare-earth scandates LaScO 3 [48], GdScO 3 [49], DyScO 3 [50], and SmScO 3 [51]. Among them, HfO 2 , HfO 2 -based materials, ZrO 2 , and ZrO 2 -based materials are considered as the most promising candidates combining high dielectric permittivity and thermal stability with low leakage current due to a reasonably high barrier height that limits electron tunneling.…”

Atomic Layer Deposition of Gadolinium Aluminate using Gd(iPrCp)3, TMA, and O3 or H2O

“…Several papers have been published on the deposition and characterization of Gd 2 O 3 using, e.g., e-beam evaporation [18][19][20][21] or radio frequency (RF) sputtering. [22] In addition, ALD was reported using Gd(thd) 3 (thd ¼ 2,2,6,6-tetramethyl-3,5-heptanedionato) in combination with O 3 , [23] or, alternatively, using Gd(CpCH 3 ) 3 (Cp ¼ cyclopentadieentadienyl), [23] Gd(mmp) 3 (mmp ¼ 1-methoxy-2-methyl-2-propoxide), [24] or tris(2,3-dimethyl-2-butoxy)Gd [25,26] in combination with H 2 O. On the other hand, a very limited number of papers report on the deposition of Gd x Al 2-x O 3 thin films, and then only by non-standard techniques, for example, sol-gel deposition.…”

Gadolinium oxide high-k gate dielectrics prepared by anodic oxidation

“…Post-oxidation annealing (POA) treatments can greatly reduce the number of interface states. Optimization of the POA treatments will further reduce the interface traps to a level similar to that of SiO 2 [13]. The crystal structure of Gd 2 O 3 films was investigated by X-ray diffraction (XRD).…”