  Niobium offers the benefit of increased operating temperatures and
frequencies for Josephson junctions, which are the core component of
superconducting devices. However existing niobium processes are limited by more
complicated fabrication methods and higher losses than now-standard aluminum
junctions. Combining recent trilayer fabrication advancements, methods to
remove lossy dielectrics and modern superconducting qubit design, we revisit
niobium trilayer junctions and fabricate all-niobium transmons using only
optical lithography. We characterize devices in the microwave domain, measuring
coherence times up to $62~\mu$s and an average qubit quality factor above
$10^5$: much closer to state-of-the-art aluminum-junction devices. We find the
higher superconducting gap energy also results in reduced quasiparticle
sensitivity above $0.16~$K, where aluminum junction performance deteriorates.
Our junction process is readily applied to standard optical-based foundry
processes, opening new avenues for direct integration and scalability, and
paves the way for higher-temperature and higher-frequency quantum devices.
