Optimization of GaAs/AlGaAs staircase avalanche photodiodes accounting for both electron and hole impact ionization

Pilotto, A.; Palestri, Pierpaolo; Selmi, L.; Antonelli, M.; Arfelli, Fulvia; Biasiol, G.; Cautero, G.; Driussi, F.; Esseni, D.; Menk, R.H.; Steinhartova, T.

doi:10.1016/j.sse.2019.107728

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…Avalanche photo-diodes (APDs) in III-V compounds are very promising with respect to silicon ones thanks to the higher atomic number of the material that allows for thinner detectors and to the larger band-gap that limits the leakage current [1], [2]. However, the APD development and optimization requires an in-depth understanding of the physical mechanisms involved in the device operation [3].…”

Section: Introductionmentioning

confidence: 99%

Experimental and simulation analysis of carrier lifetimes in GaAs/AlGaAs Avalanche Photo-Diodes

Driussi

Pilotto

Belli

et al. 2020

2020 IEEE 33rd International Conference on Microelectronic Test Structures (ICMTS)

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Extensive experimental characterization and TCAD simulation analysis have been used to study the dark current in Avalanche Photo-Diodes (APDs). The comparison between the temperature dependence of measurements and simulations points out that SRH generation/recombination is responsible for the observed dark current. After the extraction of the carrier lifetimes in the GaAs layers, they have been used to predict the APD collection efficiency of the photo-generated currents under realistic operation conditions and as a function of the photogeneration position inside the absorption layer.

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Section: Introductionmentioning

confidence: 99%

Experimental and simulation analysis of carrier lifetimes in GaAs/AlGaAs Avalanche Photo-Diodes

Driussi

Pilotto

Belli

et al. 2020

2020 IEEE 33rd International Conference on Microelectronic Test Structures (ICMTS)

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“…In the past, in-depth studies have been carried out on the behaviours of these devices regarding the doping levels of the various layers, the number of multiplication steps, and the fundamental role of the δ p-doped layer [35][36][37][38]. Thanks to these studies, it was found that a δ p-doping layer of carbon atoms of 2.5 × 10 12 cm −2 is necessary to keep the absorption region unbiased over the whole range of reverse biases, up to the breakdown voltage.…”

Section: Mode Of Operationmentioning

confidence: 99%

Synchrotron Radiation Study of Gain, Noise, and Collection Efficiency of GaAs SAM-APDs with Staircase Structure

Colja

Cautero

Menk

et al. 2022

Sensors

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In hard X-ray applications that require high detection efficiency and short response times, such as synchrotron radiation-based Mössbauer absorption spectroscopy and time-resolved fluorescence or photon beam position monitoring, III–V-compound semiconductors, and dedicated alloys offer some advantages over the Si-based technologies traditionally used in solid-state photodetectors. Amongst them, gallium arsenide (GaAs) is one of the most valuable materials thanks to its unique characteristics. At the same time, implementing charge-multiplication mechanisms within the sensor may become of critical importance in cases where the photogenerated signal needs an intrinsic amplification before being acquired by the front-end electronics, such as in the case of a very weak photon flux or when single-photon detection is required. Some GaAs-based avalanche photodiodes (APDs) were grown by a molecular beam epitaxy to fulfill these needs; by means of band gap engineering, we realised devices with separate absorption and multiplication region(s) (SAM), the latter featuring a so-called staircase structure to reduce the multiplication noise. This work reports on the experimental characterisations of gain, noise, and charge collection efficiencies of three series of GaAs APDs featuring different thicknesses of the absorption regions. These devices have been developed to investigate the role of such thicknesses and the presence of traps or defects at the metal–semiconductor interfaces responsible for charge loss, in order to lay the groundwork for the future development of very thick GaAs devices (thicker than 100 μm) for hard X-rays. Several measurements were carried out on such devices with both lasers and synchrotron light sources, inducing photon absorption with X-ray microbeams at variable and controlled depths. In this way, we verified both the role of the thickness of the absorption region in the collection efficiency and the possibility of using the APDs without reaching the punch-through voltage, thus preventing the noise induced by charge multiplication in the absorption region. These devices, with thicknesses suitable for soft X-ray detection, have also shown good characteristics in terms of internal amplification and reduction of multiplication noise, in line with numerical simulations.

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“…It can be demonstrated that the NLHD framework of Eqs 3-10 assuming electron II events localized at discrete coordinates (i.e., the conduction band steps) and no hole II exactly gives the gain and noise of Eqs 18, 19, see results in [25]. Direct comparison between Eqs 20-22 and the EBHDM of [25] has been provided in [33].…”

Section: Gain and Noise In Staircase Apdsmentioning

confidence: 99%

Modeling Approaches for Gain, Noise and Time Response of Avalanche Photodiodes for X-Rays Detection

et al. 2022

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We report on a suite of modeling approaches for the optimization of Avalanche Photodiodes for X-rays detection. Gain and excess noise are computed efficiently using a non-local/history dependent model that has been validated against full-band Monte Carlo simulations. The (stochastic) response of the detector to photon pulses is computed using an improved Random-Path-Length algorithm. As case studies, we consider diodes consisting of AlGaAs/GaAs multi-layers with separated absorption and multiplication regions. A superlattice creating a staircase conduction band structure is employed in the multiplication region to keep the multiplication noise low. Gain and excess noise have been measured in devices fabricated with such structure and successfully compared with the developed models.

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Optimization of GaAs/AlGaAs staircase avalanche photodiodes accounting for both electron and hole impact ionization

Cited by 6 publications

References 24 publications

Experimental and simulation analysis of carrier lifetimes in GaAs/AlGaAs Avalanche Photo-Diodes

Experimental and simulation analysis of carrier lifetimes in GaAs/AlGaAs Avalanche Photo-Diodes

Synchrotron Radiation Study of Gain, Noise, and Collection Efficiency of GaAs SAM-APDs with Staircase Structure

Modeling Approaches for Gain, Noise and Time Response of Avalanche Photodiodes for X-Rays Detection

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