Semiconductors have become one of the most important materials in our current world. They have allowed the information era to develop, enabling the creation of laptops, superfast computers, smartphones, tablets and other electronic devices. According to Moore's law, these materials have to continue addressing the challenges of miniaturization of electronics, by increasing the quality of the materials and the efficiency of the devices. In addition, they are also very present in energy solutions that are considered crucial in the energy transition that the world would have to follow away from fossil fuels. Firstly, energy-efficient solutions such as that of LEDs are crucial if the society is to change completely to renewable energies. In addition, semiconductors are also used as energy sources by making use of the photovoltaic effect inside of solar cells. However, the quality and efficiency of both of these devices highly depend on the quality of the materials. The challenges faced by both of these production schemes are related to the quality of the semiconductor materials used in these devices. This quality heavily depends on the initial material and on the deposition techniques used. However, a trade-off is formed in regarding these techniques. Usually, the most expensive and energy-intensive methods are the ones that yield the highest quality material. Thus, it must be identified if the limiting factor is the cost of the process or the quality of the materials used. This book explores several deposition and synthesis methods related to semiconductor devices, as well as some pre- and post-processing methods that might increase the cost but also the efficiency of the overall device. In this book, some examples of actual devices and real applications are given. Looking at the complicated architectures and numerous steps involved in a real semiconductor device, it can be seen that not only the bulk semiconductor is important, but also the processes around them. Thus, all the steps need to be carefully controlled to be able to detect any multifunction that can appear. Here, we describe some of the most common methods to identify the properties of the different layers. However, cost and efficiency are not the only considerations in semiconductor processes. The safety hazards and pollution that might be created in these processes are an increasing source of concern for both industries and governments. Thus, when considering which semiconductors to use or which processes to apply, the safety of the process must also be taken into account. Moreover, this concern can be extended to the end-of-life treatment of these devices, recycling the materials that can be recovered and safely discarding the ones that cannot be recycled. This is especially important for devices including lead, cadmium and other dangerous species. The final chapter of this book deals with the economic side of the semiconductor industry, giving an overview of the main companies involved, the trends and the scalability of these techniques. This section shows the growing trend of the semiconductor industry, together with its goals regarding lower production costs and smaller size. To meet these challenges and to be competitive, research and development activities in this field are very high. Looking at these trends, some conclusions can be drawn over the most effective processing methods and how some of their challenges could be overcome. In summary, this is a book that tries to give a comprehensive view of all the steps involved in semiconductor processing for a variety of applications. During this analysis, the main parameters to take into account would be the quality of the material, the costs and energy use associated with each process and the possible environmental and health hazards that can be created. By looking at these issues from the perspective of material science, some insight into the advantages and disadvantages of each method can be acquired, making the field advance towards more efficient, safe and cost-efficient processes.