The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 31, 1994
Filed:
May. 12, 1992
Steven L Williamson, Ann Arbor, MI (US);
University of Michigan, Ann Arbor, MI (US);
Abstract
A photoresponsive pulser/sampler system for investigating electrical signals and responses in VLSI systems employs a microtip which communicates electrically and mechanically with the device under test, and electrically with an electrode via a photoresponsive gate. The photoresponsive gate is formed of interdigitated electrodes which have interdigital spacings therebetween on the order of 1 .mu.m. The structure of the invention is operable in the dual modalities of probe and pulser which share a common probe tip. Simultaneous implementation of the pulser and sampler functions is achieved with the use of a lock-in amplifier and the technique of difference frequency mixing, where the pulser optical pulse frequency is f.sub.1 and the gate optical pulse frequency is f.sub.2. Multiple photoresponsive gates coupled to a common probe tip and having respective electrodes are disclosed for achieving respective pulsing and sampling functions, and also for effecting S-parameter measurements. The lock-in amplifier is tuned to the difference between the two frequencies (f.sub.2 -f.sub.1). Piezoelectric apparatus is employed for translating the probe tip over the device under test.