The present disclosure relates to methods of fabricating electronic devices or components thereof. The electronic devices can be vacuum electronic devices. The methods can include disposing a first material on or in a substrate. The methods can further include removing a portion of the first material to form one or more structure protruding from the substrate. The methods can further include disposing a second material onto the one or more structure of the first material, and then removing a portion of the second material to form one or more sidewall structures. A second portion of the one or more structures of the first material can also be removed to form a fabricated structure including the substrate and one or more sidewall structures protruding therefrom.