Operando hard X-ray photoelectron spectroscopy study of buried interface chemistry of Au/InO1.16C0.04/Al2O3/p+-Si stacks

Operando hard X-ray photoelectron spectroscopy (operando-HAXPES) with synchrotron radiation source was used under an applied bias voltage to investigate prototypical Au/InO1.16C0.04/Al2O3/p+-Si structure. First, HAXPES analysis reveals a successful incorporation of carbon in the In2O3 matrix (InO1.16C0.04) which is intentionally used to stabilized intrinsic oxygen vacancies and limit their harmful migrations. Results show that the InO1.16C0.04 layer tends to remove the oxygen from the Al2O3 layer and create an oxygen depletion region into the Al2O3 film subsequent to the InO1.16C0.04 deposition step. Under bias, we observe a combination of band bending from Al2O3 and redox reaction in the InO1.16C0.04. From depth dependent HAXPES measurements, we conclude that the redox process mainly takes place near the Au/InO1.16C0.04 top interface. Thanks to the HAXPES extended probing depth, we highlight that the in-operando analysis may be an effective tool for a dynamic observation of TFT buried interfaces. We hope that our operando-HAXPES measurements will contribute to develop a full understanding of interfacial structure, energy bands and TFT operation mechanisms. •Study of the chemical states of Au/InO1.16C0.04/Al2O3/p+-Si via an operando-HAXPES analysis.•Low temperature Atomic layer deposition of carbon-doped In2O3 (InO1.16C0.04) on Al2O3/p+-Si.•We report that the InO1.16C0.04 semiconducting layer sucks the oxygen species from the Al2O3.•We have highlighted a presence of band bending from Al2O3.•Redox reaction of InO1.16C0.04 at the Au/InO1.16C0.04 interfacial under an applied voltage.