A solar cell and a method of forming a contact structure on a solar cell having a p-n junction formed between a first semiconductor region of a first dopant polarity and a second semiconductor region of a second dopant polarity opposite to the first dopant polarity. The microCHP unit comprises an electric power source that is independent from the mains power supply. A guiding mechanism slidably guides the first boot connecting zone relative to the base of the device. In other embodiments, at least two spacers are combined to provide an intervertebral distracting device. These models include phased-based parameters that define amounts of material that flow into and out of a determined area for processing the materials.