3D Silicon Betavoltaics Microfabricated using a Self-Aligned Process for 5 Milliwatt/CC Average, 5 Year Lifetime Microbatteries

We report on the first demonstration of high efficiency 3D silicon betavoltaics, microtextured with deep reactive ion etched (DRIE) trenches, for potential application in 5 year lifetime 5 mW / cc Promethium -147 powered microbatteries. Prototype 3D silicon betavoltaics were designed and microfabricated in a 2-mask self-aligned process, and characterized using accelerated electron beams in a scanning electron microscope to yield 1.02 % conversion efficiency @ 30 kV acceleration voltage.