Optimal Boron Thickness in a NISC

A neutron intercepting silicon chip (NISC) comprises a silicon data storage chip coated with a layer of borophosphosilicate glass (BPSG) containing boron-10. Neutrons interact in the boron layer via neutron capture: n + B-10 -> Li-7 + He-4. The ions produced deposit charge (on the order of fC/um) over a range of several microns; when one of them passes through the data-storing oxide-nitride-oxide (ONO) layer of the chip, the charge it deposits causes a leakage across capacitors in the chip, and as a result bits flip from positive to negative. In the interests of optimizing the thickness of the boron layer, a Monte Carlo program has been written to simulate the paths of particles and their charge deposits in the charge-storing layer. The simulation shows that a significant advantage in efficiency can likely be gained by increasing the thickness of the boron layer by an order of magnitude.