The Reactive Bridge: A Novel Solid-State Low Energy Initiator

Abstract

Within a broad variety of commercial (i.e. automotive airbags, mining) and government ordnance systems there exists an interface which utilizes electrical energy to initiate an exothermic reaction (i.e. combustion, deflagration, detonation). The structure that performs this function is commonly referred to as an Electro-explosive device (EED). The basic EED design is susceptible to initiation failures due to mechanical hazards such vibration and shock. This paper discusses the fabrication and characterization of a micro-machined EED (the Reactive Bridge) which is mechanically robust, extremely reliable and inexpensive to manufacture. The structure is capable of directly initiating a wide variety of pyrotechnics and primary explosives. The Reactive Bridge offers the additional advantage of being able to be directly fabricated onto any custom integrated circuit. This feature may be of particular interest for adding anti-tamper features directly at the individual die level of electronic systems. The structure consists of patterned sequential layers of titanium and boron which react exothermically when properly initiated. Design parameters will be discussed and compared to firing data for Reactive Bridge EEDs loaded with fine grain zirconium potassium perchlorate (ZPP). A number of different sized bridges were investigated. Scanning electron microscope photographs of cross-sectioned devices before and after firing will also be discussed.