Epitaxial lift-off of freestanding (011) and (111) SrRuO3 thin films using a water sacrificial layer

Abstract

Two-dimensional freestanding thin films of single crystalline oxide perovskites are expected to have great potential in integration of new features to the current Si-based technology. Here, we showed the ability to create freestanding single crystalline (011)- and (111)-oriented SrRuO3 thin films using Sr3Al2O6 water-sacrificial layer. The epitaxial Sr3Al2O6(011) and Sr3Al2O6(111) layers were realized on SrTiO3(011) and SrTiO3(111), respectively. Subsequently, SrRuO3 films were epitaxially grown on these sacrificial layers. The freestanding single crystalline SrRuO3(011)pc and SrRuO3(111)pc films were successfully transferred on Si substrates, demonstrating possibilities to transfer desirable oriented oxide perovskite films on Si and arbitrary substrates.

Freestanding Perovskite Oxide Films: Synthesis, Challenges, and Properties

“…67 Sr 0.33 MnO 3 were successfully grown on SAO sacrificial layer and transferred onto arbitrary substrates. [ 27,28 ]…”

“…67 Sr 0.33 MnO 3 were successfully grown on SAO sacrificial layer and transferred onto arbitrary substrates. [27,28] Interestingly, by controlling the ratio between Ca, Sr, and Ba the reduced lattice parameter of (Ca,Sr,Ba) 3 Al 2 O 6 can be continuously tuned from 3.819 Å (100% Ca) to 4.124 Å (100% Ba) (Figure 2a). [57,56] For example, Ca 2 SrAl 2 O 6 was used as a seed sacrificial layer for La 0.7 Ca 0.3 MnO 3 growth due to the nearly perfect lattice match (<0.1%).…”

“…[57,56] For example, Ca 2 SrAl 2 O 6 was used as a seed sacrificial layer for La 0.7 Ca 0.3 MnO 3 growth due to the nearly perfect lattice match (<0.1%). [55] The minimization lattice mismatches SrTiO 3 [12,[19][20][21][22][23] La x Sr 1−x MnO 3 [19,28,58] BaTiO 3 [59][60][61][62][63] BiFeO 3 [64,65] SrRuO 3 [27,60] LaNiO 3 [66] BiMnO 3 [67] Sr 2 IrO 4 [68] Fe 3 O 4 [69,70] CeO 2 [71] La 0.7 Ca 0.3 MnO 3 [72] [(La 0.7 Sr 0.3 MnO 3 ) 5 /(SrTiO SrTiO 3 [32] n-SrTiO 3 /n-PbTiO 3 /n-SrTiO 3 [33] [(PbTiO 3 ) 16 /(SrTiO 3 ) 16 ] 8 [33] PPC PMMA Water RT -Sr The synthesis method of each sacrificial thin film is shown along with synthesis conditions, substrates, and etching conditions; In the table, T, P O 2 , P Ar , and E indicate the synthesis temperature, pressure of oxygen gas, pressure of argon gas, and laser energy density, respectively; The list of perovskite oxide membranes obtained, the substrate, and the transfer method are also shown; In the column of etching condition, water and RT represent deionized water and room temperature; d, h, and m denote days, hours, and minutes, respectively. can largely improve the quality of the released membranes by hindering the formation of cracks, [55] which has motivated the exploration of sacrificial layers such as Ca 2 SrAl 2 O 6 ( [56,55,[52][53][54] However, small Ca ions can make more distorted geometri...…”

Stacking and Twisting of Freestanding Complex Oxide Thin Films

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28] The methods typically rely on: 1) controllable weakening of epitaxial crystals; [16] 2) releasing thin oxide films using sacrificial interlayers and selective etching (Figure 1a); [17] and 3) self-formed freestanding oxide thin films. [18] These innovative approaches, especially the sacrificial interlayer etching method, have produced a broad range of new freestanding oxide films of, e.g., cubic SrTiO 3 , [19] BaTiO 3 , [20] BiFeO 3 , [21] SrRuO 3 , [22] pseudocubic La 0.7 Ca 0.3 MnO 3 , [23] La 0.7 Sr 0.3 MnO 3 , [24] fluorite CeO 2 , [25] BaTiO 3 /La 0.7 Sr 0.3 MnO 3 bilayers, [26] La 0.7 Sr 0.3 MnO 3 /BiFeO 3 bilayers, [27] as well as (La 0.7 Sr 0.3 MnO 3 ) n /(SrTiO 3 ) n ] n superlattices. [17] These freestanding films and multilayers exhibit a wide range of exciting physical and chemical properties combined with the option of transferring them onto arbitrary substrates, thus bypassing the epitaxial roadblock.…”

Recent Progress in Flexible Multiferroics

“…In this strategy, a sacrificial layer is placed between the functional film and the substrate that is selectively removable by a chemical etchant retaining the properties of the thin films. SiO 2 , MgO, La 0.7 Sr 0.3 MnO 3 (LSMO), and Sr 3 Al 2 O 6 (SAO) have been used as sacrificial layers [33,[36][37][38][39] for deposition of multiferroic BFO and CoFe 2 O 4 (CFO) thin films on mechanically rigid substrates such as SrTiO 3 (STO), LaAlO 3 (LAO), NdGaO 3 , and TbScO 3 . Zhang et al [29] prepared freestanding CFO epitaxial thin films by the transfer process using MgO as a sacrificial layer, where CFO epitaxial thin films were grown on MgO-buffered (001) STO substrates by the PLD technique and transferred onto flexible PI substrates.…”