Second Breakdown in the Presence of Intense Ionizing Radiation
Abstract
The role of intense pulses of ionizing radiation on the p(+) - n - p(+) diodes. Superimpsed on a high amplitude current pulse is a pulse of intense ionizing readiation from a Q-switched neodymium-glass laser. Photocurrents proportional to the radiation intensity are observed all the way to the threshold of damage by laser irradiation alone. The photocurrents do not affect the second breakdown transition until the intensity of the laser beam is close to that for destruction by the laser alone. In this regime, for diodes of high n-region resistivity, the second breakdown transition is delayed by the presence of the photocurrent pulse. This delay is associated with circuit inductance; the photocurrent pulse spike drives the voltage across the device to a low value or even reverses its polarity. Recovery of the voltage occurs with a time constant determined by the curcuit. This is sufficient time for the junction, previously heated by a current pulse, to cool appreciably. No detectable change in delay time occurs for diodes having an n-region carrier density comparable to that produced by the photopulse or for forward biased diodes. In a study of the damage produced by the laser beam alone, no heating effects are detectable right up to the damage threshold. Damage occurs by vaporization of the silicon; the absorption coefficient of silicon changes within a few nanoseconds by more than a factor of 10 at the damage threshold.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 20, 1974
- Accession Number
- ADB008854
Entities
People
- Aradhana Baruah
- Duane H. Pontius
- Paul P. Budenstein
- Wallace B. Smith
Organizations
- Auburn University