A method of triggering avalanche breakdown in a semiconductor device includes providing an electrical coupling and an optical coupling between an auxiliary semiconductor device configured to emit radiation and the semiconductor device including a pn junction between a first layer of a first conductivity type buried below a surface of a semiconductor body and a doped semiconductor region of a second conductivity type disposed between the surface and the first layer. The electrical and optical coupling includes triggering emission of radiation by the auxiliary semiconductor device and triggering avalanche breakdown in the semiconductor device by absorption of the radiation in the semiconductor device.