In true Inspector Gadget, self-destructing message fashion, military research organisation DARPA is keen to develop microchips that can "vanish" on command. Such devices would be useful in technology that risks being lost -- and subsequently captured -- in the field.
The initiative is part of DARPA's "Vanishing Programmable Resources" or VAPR program, which "seeks electronic systems capable of physically disappearing in a controlled, triggerable manner". Rather than compromising on performance or features, the disintegrating components must be "comparable to commercial-off-the-shelf electronics"... just with the option to flick the kill switch.
According to the US government's business opportunities site, IBM has been awarded $US3.45 million in funding to pursue this branch of research -- and it already has a method in mind:
IBM plans is to utilize the property of strained glass substrates to shatter as the driving force to reduce attached CMOS chips into Si and SiO2 powder. A trigger, such as a fuse or a reactive metal layer will be used to initiate shattering, in at least one location, on the glass substrate. An external RF signal will be required for this process to be initiated.
Yeah, I can imagine it being difficult to do much reverse-engineering if all you have to work with is silicon dust.