Impact of Post-Deposition Anneal on ALD Al2O3/etched GaN Interface in Gate-First MOSc-HEMT Process Flow

Pedro Fernandes Paes Pinto Rocha (1, 2) , Laura Vauche (1) , Blend Mohamad (1) , William Vandendaele (1) , Eugénie Martinez (3) , Tarek Spelta (3) , Névine Rochat (1) , Romain Gwoziecki (1) , Bassem Salem (1, 4) , Véronique Sousa (1)

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
2 UGA - Université Grenoble Alpes
3 DPFT - Département Plate-Forme Technologique
4 LTM - Laboratoire des technologies de la microélectronique

In this work, we investigate the impact of Post-Deposition Anneal (PDA) of Atomic-Layer Deposited (ALD) Al2O3 on etched GaN for MOS-channel High Electron Mobility Transistors (MOSc-HEMTs) Gate-First process flow using C-V measurements carried out on MOS capacitors (MOSCAPs). For PDA up to 500°C, a reduction of the flat-band voltage hysteresis (ΔVFB) is reported and explained by the reduction of Ga-O bonds and O-H groups observed by Hard X-Ray Photoelectron Spectroscopy (HAXPES) analysis, the latter being confirmed by Fourier Transform Infrared Spectroscopy (FTIR). For a 600°C PDA, Grazing Incidence XRD (GIXRD) analysis shows a small crystallized κ-Al2O3 signal on etched GaN, which is absent for asgrown GaN. This beginning of crystallization could explain the degradation in ΔVFB and breakdown field for PDA above 500°C observed on MOSCAPs after the Gate-First process flow overall thermal budget.

Domains: Chemical Sciences; Material chemistry; Engineering Sciences [physics]; Micro and nanotechnologies/Microelectronics

Pedro Fernandes Paes Pinto Rocha, Laura Vauche, Blend Mohamad, William Vandendaele, Eugénie Martinez, et al.. Impact of Post-Deposition Anneal on ALD Al2O3/etched GaN Interface in Gate-First MOSc-HEMT Process Flow. GaN MARATHON, Jun 2022, Venise, Italy. ⟨cea-03846232⟩