This　letter　reports　the　breakdown　ruggedness　of　GaN-based　quasi-vertical　p-i-n　diodes　on　Si　for　the　first　time.　With　a　2-mu　m-thick　drift　layer,　the　0.08-mm(2)　devices　can　sustain　a　surge　current　up　to　0.73　A,　and　maximum　sink　in　energy　of　3　mJ　using　an　unclamped　inductive　switching　test　setup.　No　parametric　drift　nor　device　degradation　was　found　after　repetitive　avalanche　test　consisting　of　multiple　50　000　breakdown　events　with　a　frequency　of　1　kHz.　At　elevated　temperatures,　the　breakdown　voltage　exhibits　little　temperature　dependence,　which　could　be　explained　by　a　trap-assisted　space-charge-limited　current　conduction　mechanism.　With　good　ruggedness　quality　under　repetitive　test　and　at　elevated　temperatures,　the　quasivertical　GaN　p-i-n　diodes　on　Si　show　great　potential　in　achieving　cost-effective　rectifiers　for　high-voltage　applications.