[20, 21]. To state the challenge more precisely, no stable buffer or substrate has been found that would allow a direct growth of borocarbides without a significant metallic or oxidic in- terdiffusion at all. While trying metallic buffers as well, most groups eventually used oxidic substrates such as magnesium oxide (MgO) or sapphire single crystals as those are chemi- cally stable up to high temperatures. During their experiments, it overall turned out that at the interface between borocarbide and oxidic substrate, a R$_{2}$ O$_{3}$ layer is formed during the deposition of the R Ni$_{2}$B$_{2}$C material. The thickness of this oxide interface layer, whose for- mation can be hindered by suitable metallic buffer layers as already mentioned[20, 21], can reach about 100 nm[27]. Moreover, epitaxial growth can be transferred from the substrate through the interfacial oxide layer leading to a textured R Ni$_{2}$B$_{2}$C phase under suitable de- position conditions. Investigations using transmission electron microscopy (TEM) revealed in detail how the in–plane alignment is transferred from the substrate to grains of the oxide interface layer and further to the borocarbide layer and located additional secondary phases at the substrate interface [27, 28]. The growth control of this buffer layer is therefore one of the key parameters for the successful preparation of epitaxial R Ni$_{2}$B$_{2}$C films. However, the availability of epitaxial R Ni$_{2}$B$_{2}$C films with appealing superconducting properties is rather limited. Various reports are present about the preparation of borocarbide thin films by sput- tering or pulsed laser deposition (PLD), explicitly aiming for well–aligned textured R Ni$_{2}$B$_{2}$C layers, high critical temperatures close to bulk values and high residual resistivity ratios, but achieving sufficient properties reproducibly at the same time has been reported only rarely. Mainly, two groups reported on significant progress in growing highly textured as well as in–plane ordered borocarbide thin films with good superconductive properties at the same time [20, 22]. In this report, the preparation of epitaxial LuNi$_{2}$B$_{2}$C thin films is presented starting from the target production until the final thin film samples. LuNi$_{2}$B$_{2}$C was chosen because it is a non magnetic borocarbide and has the highest critical temperature of all stable rare earth nickel borocarbides. Single crystals of LuNi$_{2}$B$_{2}$C show a superconducting transition temperature of up to 16.5 K [29]. MgO(110) substrates are used which can lead to an improved in–plane texture in comparison to MgO(100) substrates[30]. The growth parameters are therefore adapted for the use of these substrates enabling the reproducible synthesis of epitaxial superconducting LuNi$_{2}$B$_{2}$C thin films showing critical temperatures close to 16 K and residual resistivity ratios up to 15 in the as-prepared state. The paper is structured as follows: First, the sample preparation is explained in detail. The structural 3