Atomic Layer Deposition of Gd₂O₃ and Dy₂O₃: A Study of the ALD Characteristics and Structural and Electrical Properties

Abstract

Gd2O3 and Dy2O3 thin films were grown by atomic layer deposition (ALD) on Si(100) substrates using the homoleptic rare earth guanidinate based precursors, namely, tris(N,N'-diisopropy1-2-dimethylamido-guanidinato) gadolinium (III) [Gd(DPDMG)(3)] (1) and tris (N,N'-diisopropyl-2-dimethylamido-guanidinato)dysprosium (III) [Dy(DPDMG)(3)] (2), respectively. Both complexes are volatile and exhibit high reactivity and good thermal stability, which are ideal characteristics of a good ALD precursor. Thin Gd2O3 and Dy2O3 layers were grown by ALD, where the precursors were used in combination with water as a reactant at reduced pressure at the substrate temperature ranging from 150 degrees C to 350 degrees C. A constant growth per cycle (GPC) of 1.1 angstrom was obtained at deposition temperatures between 175 and 275 degrees C for Gd2O3, and in the case of Dy2O3, a GPC of 1.0 angstrom was obtained at 200-275 degrees C. The self-limiting ALD growth characteristics and the saturation behavior of the precursors were confirmed at substrate temperatures of 225 and 250 degrees C within the ALD window for both Gd2O3 and Dy2O3. Thin films were structurally characterized by grazing incidence X-ray diffraction (GI-XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM) analyses for crystallinity and morphology. The chemical composition of the layer was examined by Rutherford backscattering (RBS) analysis and Auger electron spectroscopy (AES) depth profile measurements. The electrical properties of the ALD grown layers were analyzed by capacitance voltage (C-V) and current-voltage (I-V) measurements. Upon subjection to a forming gas treatment, the ALD grown layers show promising dielectric behavior, with no hysteresis and reduced interface trap densities, thus revealing the potential of these layers as high-k oxide for application in complementary metal oxide semiconductor based devices

Atomic Layer Deposition of Groups 4 and 5 Transition Metal Oxide Thin Films: Focus on Heteroleptic Precursors

“…Several alkoxide‐donor‐functionalized alkoxide precursors have been reported in the literature . ( t BuO) 2 Zr(dmae) 2 and ( i PrO) 2 Zr(dmae) 2 , together with water as the oxygen source, do not undergo self‐limiting growth and were reported to decompose at temperatures as low as 240°C .…”

“…( t BuO) 2 Zr(dmae) 2 and ( i PrO) 2 Zr(dmae) 2 , together with water as the oxygen source, do not undergo self‐limiting growth and were reported to decompose at temperatures as low as 240°C . Only the studies on the growth of HfO 2 and TiO 2 thin films that used water and ( t BuO) 2 Hf(mmp) 2 or ( i PrO) 2 Ti(dmae) 2 , reported self‐limiting growth, however high carbon and hydrogen contamination was found in the films grown from ( t BuO) 2 Hf(mmp) 2 . The self‐limited growth of TiO 2 from ( i PrO) 2 Ti(dmae) 2 was demonstrated at the low temperature of 100°C, but no compositional data were reported.…”

Electrical characterization of MIS capacitors based on Dy<inf>2</inf>O<inf>3</inf>-doped ZrO<inf>2</inf> dielectrics

“…Rare earth (RE) oxide based materials have also been studied for both logic and memory applications because of their high permittivity values, large band gaps and better stability when deposited directly on silicon. Dysprosium oxide (DY203) is one of the RE oxides studied [5][6]. It has a dielectric constant value ranging from 14 to 18, an energy band gap of 4.9 eV and high thermal and chemical stability when deposited directly on silicon.…”

Dysprosium oxide and dysprosium-oxide-doped titanium oxide thin films grown by atomic layer deposition

“…Dysprosium and dysprosium oxide have been materials of interest for a long time [1][2][3][4][5][6][7][8][9] as dysprosium is a lanthanide metal with the largest magnetic moment and susceptibility. 2 In addition, combination of polymeric architectures with dysprosium ions can produce hybrid materials with extremely rich properties.…”

“…Dysprosium oxide has been considered as a candidate of high-permittivity (high-k) capacitor dielectric for nonvolatile memory applications 3 and as a high-k gate dielectric. [4][5][6] Regarding the performance of Dy 2 O 3 as essentially a paramagnetic oxide, standards in the form of Dy 2 O 3 powders have been exploited for quantum interference magnetometer, 7 vibrating sample magnetometer (VSM), 8 or in the form of small single crystals as additive seeds for superconducting materials for a susceptometer. 9 Dysprosium-doped polymers and glasses can emit white light, 10,11 while Dy:PbGa 2 S 4 compound has been shown to be a solid state laser material emitting at 4.32 lm when pumped by 1.7 lm laser diodes.…”