Nonlocal effects in thin 4H-SiC UV avalanche photodiodes

Abstract

ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. ) for hole (electron) injection, was measured with 365-nm light in both structures. Modeling the experimental results using a simple quantum efficiency model and a nonlocal description yields effective ionization threshold energies of 12 and 8 eV for electrons and holes, respectively, and suggests that the dead space in 4H-SiC is soft. Although dead space is important, pure hole injection is still required to ensure low excess noise in thin 4H-SiC APDs owing to ratios that remain large, even at very high fields.

A comparison of avalanche breakdown probabilities in semiconductor materials

“…The threshold energies in [7][8][9][10] resulted in 0.02<d/w<0.05 for the 2 mm thick SPADs simulated. To check if the presence of such significance of dead space affects the comparisons between different materials in figure 2(a), we artificially let d e ¼ d h ¼ 0 by assuming E the ¼ E thh ¼ 0 while still using the same à (F ) and à (F ) to obtain another set of results for the materials considered, as shown in figure 2(b).…”

“…The effective ionization coefficients and the threshold energies for these materials are obtained from [6][7][8][9][10][11][12]. Due to the lack of published data E the ¼ E thh ¼ 0 is assumed for Ge, which is reasonable because of its small bandgap and hence small threshold energies.…”

Relating the Experimental Ionization Coefficients in Semiconductors to the Nonlocal Ionization Coefficients

“…from the DSMT model for a wide range of semiconductor materials like Si [26], InP [27], SiC [28], Al 0.6 Ga 0.4 As [29], Al 0.8 Ga 0.4 As [30], In 0.52 Al 0.48 As [31], and Ga 0.52 In 0.48 P [32] agree surprisingly well with the experimental data, provided good knowledge of α (β ) and their corresponding E the (E thh ) exists, as shown in Table I. The effective threshold energy in the DSMT model is the mean energy carriers attain before impact ionization, and as such it differs from other definitions in [33]- [35].…”

Impact Ionization in Ion Implanted 4H-SiC Photodiodes

“…Nevertheless, most of the impact ionization results [8][9][10][11] reported to date are based on p-n diodes fabricated from heavily doped n-type and p-type 4H-SiC epitaxial structures and they show wide variations. Nevertheless, most of the impact ionization results [8][9][10][11] reported to date are based on p-n diodes fabricated from heavily doped n-type and p-type 4H-SiC epitaxial structures and they show wide variations.…”

“…Nevertheless, most of the impact ionization results [8][9][10][11] reported to date are based on p-n diodes fabricated from heavily doped n-type and p-type 4H-SiC epitaxial structures and they show wide variations. In Ng et al's work [10], both the multiplication and excess noise characteristics of submicron 4H-SiC diodes were interpreted using a non-local model which takes into account the dead space effect, non-uniform electric field and wavelength dependent carrier injection profiles. In Ng et al's work [10], both the multiplication and excess noise characteristics of submicron 4H-SiC diodes were interpreted using a non-local model which takes into account the dead space effect, non-uniform electric field and wavelength dependent carrier injection profiles.…”