SMU RF TRANSISTOR STABILITY ARRANGEMENT

摘要

An RF testing method and system by which a DC measurement pathway can also act like a properly terminated RF pathway. Achieving this requires that the output HI, LO, and Sense HI conductors are terminated in a frequency selective manner such that the terminations do not affect the SMU DC measurements. Once all SMU input/output impedances are controlled, as well as properly terminated to eliminate reflections, the high-speed devices will no longer oscillate during device testing, so long as the instruments maintain a high isolation from instrument-to-instrument (separate instruments are used on the gate and drain, or on the input and output of the device). The output of HI, LO and Sense HI conductors are coupled to various nodes of the DUT via three triaxial cables, the outer shieldings of which are coupled to each other and to an SMU ground.

主权项

1. A method for testing a device under test (DUT), comprising:
connecting a first Source Measurement Unit (SMU) including at least three test points to a first set of at least three triaxial cables, each triaxial cable having at least a center signal conductor, an outer shielding, a middle conductor, and a ground terminal so that each of the three test points is connected to a first end of the center signal conductor of each of the first set of the three triaxial cables, respectively, and where each of the outer shieldings of the first set of triaxial cables is electrically coupled together along with the ground terminal; connecting a second end of each of the first set of triaxial cables to a set of nodes of the device under test; connecting a second SMU including at least three test points to a second set of at least three triaxial cables and having a center signal conductor, outer shielding, a middle conductor, and a ground terminal so that each of the three test points is connected to a first end of the center signal conductor of each of the second set of the three triaxial cables, respectively, and where each of the outer shieldings of the second set of triaxial cables is electrically coupled together along with the ground terminal; connecting a second end of each of the second set of triaxial cables to the set of nodes of the device under test; wherein the outer shielding of both the first and second set of triaxial cables are electronically coupled together and electrically coupled to their respective ground terminals.