Instabilities in avalanche diodes under quasistationary and under transit-time conditions

This paper presents theoretical and experimental investigations on p-⁺-n-i-n⁺and p⁺-n-n⁺silicon avalanche diodes at high current densities. Device and operating parameters are: Width of the n-i and n depletion layers 2-5/um, n doping concentrations 10¹⁶- 10¹⁷cm^-3, current densities 10³-10⁴A/cm². Under these conditions the space-charge of the free carriers leads to a stationary differential negative resistance. This can be seen from theoretical calculations and experimental current-voltage characteristics, if certain critical current densities are exceeded. Oscillations in the 1-2 GHz range are produced due to this mechanism; they exhibit mechanical and weak electronic tuning.