A bone graft delivery system includes a bone graft injector and an access portal. A silicon nitride layer and a silicon oxide layer which is formed by oxidizing the silicon nitride layer are stacked as a gate insulating layer, and crystals grow from an interface of the silicon oxide layer of the gate insulating layer to form a microcrystalline semiconductor layer; thus, an inverted staggered thin film transistor is manufactured. The determination is made by processing directed links in a graph that includes one or more links and two or more nodes. A horizontal handlebar is positioned at the top of the combination and serves to steer the front wheel during scooter mode. 5 or more, and a second upper gate electrode made of semiconductor doped with impurities.