GAAS IC TESTING .1. PROBING THE LIMITS OF TRADITIONAL MMIC TEST EQUIPMENT

Now that commercial GaAs ICs and MMICs have reached quantity production, the industry has found that one of its most severe limitations is testing them at high speeds and high frequencies, without disturbing the circuit operation or damaging the delicate structures on the wafer. Noninvasive access to the internal signals within the circuits would solve the more complex problem of full characterization of complex high-speed ICs in engineering development and production testing. A direct electrooptic sampling measurement technique that allows for internal-node voltage measurements in GaAs ICs with picosecond time resolution, corresponding to bandwidths in excess of 100 GHz, is under development at Stanford University. The authors describe state-of-the-art GaAs MMIC and digital IC test techniques and equipment.