Using helium as background gas to avoid hydrogen brittleness for MgB2 film fabrication on niobium substrate by HPCVD

•Investigating the possibility of depositing MgB2 films on niobium substrates in other gases rather than hydrogen to suppress the hydrogen brittleness.•Comparing the phase purity, surface morphology and superconducting properties of the MgB2 films prepared in hydrogen, helium, nitrogen and argon.• The MgB2 film fabricated in helium shows similar properties with the film deposited in hydrogen and exhibits better ductility.