High-speed, high-impedance external photoconductive-type sampling probe/pulser
US5317256A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 1992 |
| Grant date | May 31, 1994 |
| Priority date | — |
| Expiry date | May 12, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R1/06772
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.