# Field and carrier current density profiles in linearly graded silicon avalanche diodes

TL;DR: In this article, a detailed study for the d.c. field and carrier current density profiles of linearly graded double drift avalanche diodes is presented taking into account the effect of impurity and mobile charge density and the realistic field dependance of the ionization rates and drift velocities for the charge carriers.

Abstract: A detailed study for the d.c. field and carrier current density profiles of linearly graded double drift avalanche diodes is presented taking into account the effect of impurity and mobile charge density and the realistic field dependance of the ionization rates and drift velocities for the charge carriers. The study involves finding the location and magnitude of the electric field maximum by an iterative method. A small shift in the position of the electric field maximum towards the p-side of the metallurgical junction is observed which increases with increasing current density and decreasing doping gradient. The maximum field and the depletion layer width change sharply with doping gradient but very slightly with d.c. current density. Over a larger fraction of the depletion layer, hole current density exceeds electron current density and hole dominance increases with decreasing doping gradient. The avalanche centre where Jp = Jn is found to be always on the n-side of the junction.

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Bell Labs

^{1}TL;DR: In this article, the ionization rates of charge carriers in silicon have been measured and fit to the recent theoretical calculations of Baraff; in contrast, none of the existing published data could fit to these theoretical curves.

Abstract: The ionization rates of charge carriers in silicon have been measured and fit to the recent theoretical calculations of Baraff; in contrast, none of the existing published data could be fit to these theoretical curves The study has been made using microplasma-free junctions of demonstrably high, uniform local multiplication A new and considerably simplified approach to the problem of extracting the ionization rates from the multiplication data has been used By employing much more precise control of the electron and hole currents used to initiate the multiplication process, the hole ionization rate at electric fields less than 300 kV/cm is found to be more than an order of magnitude smaller than any previously published measurements Hole and electron ionization rates have been measured in the same junction and consequently in the identical scattering environment The threshold energy is determined to be ${E}_{g}\ensuremath{\le}{E}_{i}\ensuremath{\le}15{E}_{g}$, and the mean free path for scattering of high-energy electrons is $50 \AA{}\ensuremath{\le}{\ensuremath{\lambda}}_{e}\ensuremath{\le}70 \AA{}$ and for energetic holes $30 \AA{}\ensuremath{\le}{\ensuremath{\lambda}}_{h}\ensuremath{\le}45 \AA{}$ Measurement of ionization rates at various temperatures substantiates the assumption that the energy-loss mechanism is the emission of optical phonons In addition, significant differences of the electrical breakdown characteristics of microplasma-free junctions are discussed as well as their preparation

457 citations

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TL;DR: In this paper, high efficiency silicon double-drift IMPATT diodes with a low-high-low doping profile structure are proposed, with efficiencies of 25 percent for 12 GHz, 24 percent for 18 GHz, and 19 percent for 50 GHz.

Abstract: High-efficiency silicon double-drift IMPATT diodes with a low-high-low doping profile structure are proposed. Devices with efficiencies of 25 percent for 12 GHz, 24 percent for 18 GHz, and 19 percent for 50 GHz, are Predicted by numerical calculations.

14 citations