Samsung Electronics Co.’s chip unit plunged a far bigger-than-expected 94% in the June quarter, reflecting the depth of a slump that’s plaguing the world’s largest memory chipmaker.Most Read from Bloo

Samsung Electronics just scored a $16.5 billion deal with Tesla tied to its Austin-area chip fab. Samsung is relying on the deal and others like it to aid its slumping semiconductor business.

Just a few years ago, Samsung Electronics stood as a leading force in the global semiconductor race, dominating one chip sector and eyeing Taiwan’s TSMC in the battle for supremacy in another.