This forms the little groove looking patterns that you see in a cell. These are called crystalline cells. From Silicon which is usually deposited in a high temperature vapor process onto sheets of stainless steel or other backing. This is called thin film . There is no basic difference in how the two types work.
Thin film is cheaper, but takes up more area for the same power output.
The main effect to the user is only that thin film panels are larger for the same power rating. Since you are buying Watts and not efficiency, there is little or no advantage to paying for the super-efficient panels unless you are very tight on space. Although thin film panels were supposed to end up being cheaper, that has not happened to any great degree. Thin film panels do not lose as much power at high temperatures - all panels lose power when hot, but the drop off is less. These differences are not great, but if other factors are equal it may be the deciding reason.