Display substrates, methods of manufacturing the same and display devices including the same

A method of manufacturing a display substrate, comprising:

• providing a base substrate comprising a first region and a second region;
• forming a dummy layer, a buffer layer, and an active layer sequentially on the base substrate;
• partially etching the active layer, the buffer layer, and the dummy layer such that a first dummy pattern, a first buffer layer pattern, and an active pattern sequentially stacked on the base substrate are formed on the first region, and a second dummy pattern, a second buffer layer pattern, and a dummy active pattern sequentially stacked on the base substrate are formed on the second region;
• forming a gate insulation layer covering the active pattern and the dummy active pattern on the base substrate;
• forming a gate electrode which is superimposed over the active pattern on the gate insulation layer;
• partially etching the gate insulation layer using the gate electrode as an etching mask;
• forming an insulating interlayer covering the gate electrode and the dummy active pattern on the base substrate;
• and
• forming a source electrode and a drain electrode electrically connected to the active pattern through the insulating interlayer.