METHOD OF PROCESSING LAYERED STRUCTURES

A method of processing a stack of layers to provide a stack of discrete layer elements, comprises the steps of: providing a stack of layers comprising: #a first layer () provided by a first material; #a third layer () provided by a solid electrolyte; and #a second layer () located between the first and third layers, the second layer having a thickness of at least 500 nm and being provided by a second material comprising at least 95 atomic % amorphous silicon; removing a through-thickness portion of the first layer () to form a first discrete layer element () provided by the first material; removing a through-thickness portion of the second layer () to form a second discrete layer element () provided by the second material, the second discrete layer element being located between the first discrete layer element () and the solid electrolyte; and etching the third layer () using the second discrete layer element () as an etching mask, to form a third discrete layer element () provided by the solid electrolyte; wherein the first, second and third discrete layer elements provide the stack of discrete layer elements.