## 1 Introduction  
Over the past few decades, copper has been used as an interconnecting metal in semiconductor technology. It replaces the previously used aluminum. However, it has been observed that the use of copper leads to its diffusion into the active regions of semiconductor devices. This is because copper atoms have the highest diffusion coefficient values in silicon (germanium) compared to other metals [1]. The problem of copper diffusion in semiconductors and methods for its prevention have attracted the interest of researchers. One technique is to use materials such as TiN [2], Ta/TaN [3], TaC [4], and MnSiO3 [5]. In addition, amorphous carbon can be used as a barrier against Cu diffusion in Cu/SiO\({}_{2}\)/Si systems [6]. A review of contemporary copper-diffusion-blocking layers and techniques for their production can be found in the work of [PERSON] et al. [7]. The problem of preventing Cudiffusion also concerns the applications of semiconductors in solar cells, where copper is used to form contacts [8]. The problem of the diffusion mechanism, its speed, and its temperature dependencies has been considered for a long time. Various techniques were used in these studies to experimentally track the diffusion of copper atoms in various materials, including metal oxides. The paper by [PERSON] and [PERSON] [9] presented an extensive study of the diffusion of radioactive copper in Cu\({}_{2}\)O. The sample was prepared in a polycrystalline form and tested at temperatures of 700-1153 \({}^{\circ}\)C for various partial pressures of oxygen (greater than 10\({}^{-6}\) atm). It was shown that the self-diffusion coefficient depends on both these parameters, i.e., the partial pressure of oxygen and the temperature (according to the Arrhenius equation). The paper also presented a model of defects in the Cu\({}_{2}\)O lattice, which was adjusted to the results of the measurement of the diffusion and electrical conductivity of copper oxides. By analyzing the dependence of the diffusion coefficient on the oxygen pressure, the authors showed that the diffusion of copper cations takes place through copper vacancies, i.e., singly charged and neutral copper vacancies. The determination of the diffusion coefficient D of copper in the copper oxide Cu\({}_{2}\)O was also covered by [PERSON] et al. [10]. The research method was similar to the work of [PERSON] [9], that is, the penetration of radioactive copper into the copper oxide layer was monitored. The linear dependence of the ln (D) as a function of the reciprocal temperature in the air atmosphere was found. It is also possible to determine the diffusion coefficient by other methods, e.g., from oxidation kinetics, if only the scale is compact, single-phase, and is formed by the diffusion of one type of species. In [11], the diffusion coefficient of Cu in Cu\({}_{2}\)O was determined from measurements of the oxidation kinetics, which were determined thermogravimetrically. Similar studies were carried out by [PERSON] et al. [12]. In addition, they presented a detailed description of the diffusion of metal cations and oxygen anions in the investigated copper oxide. Experimentally, Cu\({}_{2}\)O oxidation can be studied using transmission optical spectroscopy [13]. On this basis, the change in the energy gap during oxidation was assessed, allowing for the determination of the fraction of CuO and the rate of phase change from Cu\({}_{2}\)O to CuO. In the initial stage of this process, the rate of oxidation is logarithmic. It later changes to parabolic, and at high temperatures it becomes exponential. Studies have also shown that the oxidation process takes place in a planar and uniform front, in contrast to copper oxidation, where grain boundaries are the main oxidation pathway [13]. XRD is another method for studying the oxidation of Cu\({}_{2}\)O to CuO. In the work of [PERSON] et al. [14], due to the normalized integration of the peak areas of the XRD signal, it was possible to determine how changes in the oxide phases occur over time.