The　degradation　mechanism　of　Ti/Pt/Au　ohmic　contacts　to　p-GaAs　was　identified　experimentally　under　high　direct-current　density　stress　in　detail.　A　revised　measuring　structure　was　designed　based　on　the　circular　transfer　length　method　(CTLM),　in　which　the　high　current　density　of　0.8　x　10(5)　A/cm(2)　was　applied　vertically,　while　the　contact　resistance　was　measured　horizontally　between　two　contact　electrodes.　According　to　revised　CTLM,　the　specific　contact　resistance　was　measured　during　stress.　The　results　indicated　that　specific　contact　resistance　showed　an　exponential　dependence　on　the　aging　time.　The　depth　profiling　results　obtained　from　the　Auger　electron　spectroscopy　showed　that　Pt　penetrated　into　the　Au　layer　during　stress.　Furthermore,　some　voids　were　observed　at　the　Au/Pt　interface,　and　intermixing　began　to　form　within　metal　layer　during　stress.　These　results　demonstrated　that　the　degradation　of　Ti/Pt/Au　ohmic　contacts　to　p-GaAs　was　attributed　mainly　to　the　electromigration　and　Joule　heating　along　the　current　direction　under　high　current　density.