【Device Papers】Large positive Vғʙ shift achieved by a band alignment modulated with insertion of Ga₂O₃ dipole layer

      Researchers from the Fudan University have published a dissertation titled "Large positive VFB shift achieved by a band alignment modulated with insertion of Ga₂O₃ dipole layer" in Applied Physics Letters.

Abstract

      In this Letter, a Ga₂O₃ dipole layer deposited at the SiO₂/HfO₂ interface by in situ atomic layer deposition (ALD) has been demonstrated to be a great positive dipole. Through the in situ ALD of 10–30 cycles Ga₂O₃ dipole layer, a 1.09–1.59 V flatband voltage positive modulation range is obtained with a small 0.05–0.36 nm equivalent oxide thickness penalty, respectively. The modification of the band alignment is verified by x-ray photoelectron spectroscopy measurement on the gate stacks before and after Ga₂O₃ dipole layer insertion. The valence band offset between SiO₂/HfO₂ has been suppressed by the insertion of Ga₂O₃, proving a p-type dipole nature of Ga₂O₃ dipole layer. The first interface of SiO₂/Ga₂O₃ more dominantly decides the p-type nature, and the second Ga₂O₃/HfO₂ suppresses it. This work indicates that ALD of Ga₂O₃ is a promising positive dipole candidate for multiple threshold voltage technology in advanced process nodes.

DOI：

https://doi.org/10.1063/5.0252518