This is difficult to answer.
Limiting things to ASICs, you've got Butterfly Labs as one of the early attempts that at least went into production - but their chip wasn't the first to market. Avalon (the original) was the first to market with confirmed delivery of a chip to Jeff Garzik back in December of 2012. The idea for a Bitcoin mining ASIC has been around much longer, though, with some attempts (but not into production) as far back as April 2012. See
https://en.bitcoin.it/wiki/List_of_Bitcoin_mining_ASICs for some more information. Note that the dates there are only as good as the information that could be found; check the sources if you need this for a paper or other academic venture.
However, if you also accept FPGAs, then there were was much earlier 'dedicated' (they could always be reprogrammed again) Bitcoin mining hardware. I, for one, don't quite know who was the first in the arena to build an FPGA miner that was dedicated to the task (and not an existing FPGA evaluation / development board with a Bitcoin mining bitstream put on there). If nobody else knows off-hand or has that information compiled somewhere, do what I did for
FPGAs ASICs: search the internet
Tools like limiting the search by dates helps *a lot* to narrow things down. The X6500 and ModMiner (Quad) were definitely dedicated Bitcoin mining devices (as made obvious by silkscreen markings), whereas the Ztex devices, Cairnsmore, and I think the original Icarus were all technically development boards. There's also a few other designs by ngzhang (Avalon) that qualify more as a development board than a dedicated Bitcoin miner, even though he designed them with Bitcoin mining in mind.
