Room-Temperature Atomic Layer Deposition of Elemental Antimony

Abstract

Atomic layer deposition (ALD) of elemental antimony was achieved on hydrogen-terminated silicon (H–Si) and SiO2/Si substrates using Sb­(SiMe3)3 and SbCl3 in the temperature range 23–65 °C. The mirrorlike films were confirmed to be composed of crystalline antimony by XPS (for the film deposited at 35 °C) and XRD, with low impurity levels and strong preferential orientation of crystal growth relative to the substrate surface. To the best of our knowledge, this is the first example of room-temperature thermal ALD (with demonstrated self-limiting growth) of a pure element. Film growth at 35 °C exhibited a substrate-enhanced mechanism, characterized by faster film growth for the first ∼125 ALD cycles, where substantial deposition occurs on the original substrate surface (GPC = 1.3 Å/cycle on SiO2/Si and 1.0 Å/cycle on H–Si) and slower film growth (GPC = 0.40 Å/cycle on SiO2/Si and 0.27 Å/cycle on H–Si) after ∼125 cycles, once much of the initial substrate surface has been covered. Films deposited using 500–2000 ALD cycles were shown to be continuous by SEM. The use of less than 250 cycles afforded discontinuous films. However, in this initial growth phase, when the deposition occurs primarily on the original substrate surface, in situ surface pretreatment by Sb­(SiMe3)3 or SbCl3 (50 × 0.4 or 0.8 s pulses) followed by the use of longer precursor pulses (0.4 or 0.8 s) during the first 50 ALD cycles resulted in improved nucleation. For example, on H–Si, a continuous 6.7 nm thick film was produced after initial pretreatment with 50 × 0.8 s pulses of SbCl3, followed by 50 ALD cycles using 0.8 s pulses. The use of longer pulses in the first 50 ALD cycles following surface pretreatment is likely required to achieve complete reactivity with an increased density of reactive surface sites.

Atomic Layer Deposition Route to Scalable, Electronic-Grade van der Waals Te Thin Films

“…In summary, ALD-Te follows the substrate-enhanced (Stage #1) and film growth model (Stage #2). This growth tendency is in agreement with that previously reported in atomic-layer-deposited vdW films, such as MoS 2 , WS 2 , SnS 2 , and Sb …”

“…Figure a presents a schematic illustration of a shower-head type reactor designed to bring the key technical benefits of ALD into the growth of vdW Te thin films. In particular, two liquid-phase Te precursorsTe­(OEt) 4 and Te­(SiMe 3 ) 2 are employed to promote reactivity even at low deposition temperatures, as similarly performed for covalently bonded elemental thin films, such as ALD-grown Sb . Additionally, MeOH, discussed in more detail in the following section, is added as a co-reactant of Te­(SiMe 3 ) 2 and as a chemisorption promoter.…”

Block Copolymer Approach toward Selective Atomic‐Layer Deposition of ZnO Films

“…[21][22][23][24] The unique way of separating the different precursor gas doses in ALD by sequential precursor pulsing and inert gas purging enables the growth of homogeneous pinhole-free thin films with atomic-layer accuracy even on large-area surfaces. [17,19] Moreover, owing to the high reactivity of ALD precursors, these films can be deposited under relatively mild conditions, even at room temperature, [25][26][27] which makes the technique compatible with sensitive substrates such as polymers [28][29][30][31][32] for various applications including gas barrier layers for food or medicine package [33][34][35][36] and in flexible electronics. It should be also emphasized that ZnO is one of the prototype ALD materials for which the deposition process/parameters from diethyl zinc (DEZ) and water precursors are well established for conventional substrate materials (silicon, glass).…”