High speed semiconductor characterization technique

Claim 1

A test system for evaluating LSI arrays of photodiodes with an isolated electrode for each diode and a common electrode for all diodes comprising: a vacuum chamber including an externally moveable coolable stage means for mounting said array within said chamber; an electron beam generator mounted on said chamber and focussed on only one isolated electrode of said array; an externally mounted tuneable laser attached to said chamber with a beam irradiating all diodes in same array; a current conducting measuring means coupled only between the common electrode of said array and said electron beam generator to measure the electro-optical response of each photodiode as function of current between said generator and said common electrode as well as secondary electron emission from said isolated electrode; and a pulse generating means coupled between said common electrode, said beam generator and said laser to redirect the beam from said generator sequentially to each of at least a first set said diodes and to sequentially tune said laser to a plurality of optical frequencies, such that each diode may be irradiated by said plurality of frequencies.