First-principles investigation of amorphous n-type In2 O3 for BEOL transistor

The electronic transport properties of amorphous In$_{2} \mathrm{O}_{3}(\mathrm{a} - In _{2} \mathrm{O}_{3})$ are investigated from first principles simulations for BEOL transistor application. It is determined that local atomic and electronic structure disorders in a-In 2 O 3 are the fundamental origin of reduced mobility in amorphous phase. Medium range order In-In connectivity is responsible for the electron conduction pathway. It is found that amorphous disorder present in a-In 2 O 3 could induce shallow donor states and acceptor states that are responsible for the device threshold voltage instability. Nonstoichiometric defects including indium vacancy and interstitial will further increase the density of these defect states intrinsic to a-In 2 O 3 . The results could provide a better understanding of the electronic transport behavior in a-In 2 O 3 and useful insights for future defect controlling for better device performance.