High-responsivity silicon p–i–n mesa-photodiode

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The paper investigates the collection coefficient of minority charge carriers in silicon p-i-n photodiodes and the influence of certain technological factors on it. It has been found that the diffusion length of minority charge carriers and the resistivity of the material have a significant effect on the value of the collection coefficient, since the collection area of photogenerated charge carriers increases with increasing these parameters. It was also found that an effective method to increase the collection coefficient of photodiodes is to ensure that the thickness of the high-resistance region of the photodiode is equal to the sum of the diffusion length of minority charge carriers and the width of the space charge region. The effect of the concentration of dopants on the responsivity and collection coefficient is investigated. It was found that, in contrast to the calculated data, in which the collection coefficient increases with decreasing concentrations of phosphorus and boron, in the experimental data, with decreasing concentrations of impurities, the responsivity and, accordingly, the collection coefficient decrease due to a decrease in the degree of heterogenization and, as a result, a decrease in the width of the space charge region and the diffusion length of minority charge carriers.

Section: Results Of the Research And Their Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Study of the Charge Carrier Collection Coefficient of Silicon p-i-n Photodiodes

Kukurudziak,

Maistruk

2024

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“…As for the p-regions of PD [100] , in this case N dis ≈1•10 5 -2•10 5 cm -2 . Note that the increased density of dislocations provokes an increase in the surface generation component of the dark current (I d surf ) [19]: where σ ss is capture cross-sectional area; N ss -density of surface states; А p-n -is the area that contributes to the surface component of the dark current; v drift -is the average relative (relative to the center of re-combination) velocity of thermal charge carriers. The influence of these defects and their number on I d can be explained in several ways.…”

Section: B) Study Of Dark Currents Of Photodiodesmentioning

confidence: 99%

Influence of silicon characteristics on the parameters of manufactured photonics cells

Kukurudziak,

Lipka

2023

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The paper investigates the influence of the electrophysical characteristics of silicon on the final parameters of photoelectronic elements using p-i-n photodiodes as an example. It has been found that photodiode samples made on the basis of silicon with a higher resistivity are more prone to the formation of inversion channels at the oxide-semiconductor interface. Also, the dark current and responsivity of such photodiodes reach saturation at a lower voltage. It has also been shown that silicon-based photodiodes with a longer lifetime of non-basic charge carriers have lower dark current values. It has been shown that products with crystallographic orientation [111] have a much lower density of surface dislocations after technological operations than in the case of silicon with orientation [100]. It was also found that materials with different crystallographic orientations have different phosphorus diffusion coefficients. It has been experimentally established that a silicon oxide film grows faster on the surface of crystallographic orientation silicon [111] than on the surface of crystallographic orientation silicon [100]. This is due to the difference in the surface density of silicon atoms inherent in different crystallographic planes.

“…However, no information was found about the optimal options for isolating the REs of multi-element photodiodes. But it is known that often photodiode matrices or actually multi-element photodetectors are made in the form of mesastructures [12,13]. Classical planar structures are usually insulated with silicon oxide films formed in a single technological process with diffusion of acceptors or donors or silicon nitride films [4,14].…”

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confidence: 99%

Isolation of Responsive Elements of Planar Multi-Element Photodiodes

Kukurudziak

2023

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In the mass production of multi-element silicon p-i-n photodiodes, the problem of systematic rejection of products due to a decrease in the insulation resistance between the active elements of photodetectors has been revealed. The purpose of this work is to study the causes of insulation resistance degradation and to establish optimal methods for avoiding this phenomenon. A comparative analysis of three insulation methods was carried out: classical insulation by the surface of a non-conductive substrate and a dielectric layer; insulation by means of mesaprofile grooves with a dielectric film; insulation by means of areas of limitation of surface leakage channels isotypic with the substrate material (in this case, p+-type) formed in the gaps between active elements. The study found that the reason for the deterioration of the insulation resistance between the active elements of photodiodes is the presence of conductive inversion channels at the Si-SiO2 interface due to the use of silicon with high resistivity. One mechanism for the formation of inversion channels is the redistribution of impurities in the masking oxide (in particular, phosphorus) and their diffusion to the interface during thermal operations. Another mechanism for the formation of inversion layers is the diffusion of boron from silicon into SiO2 during heat treatment due to the fact that the boron segregation coefficient is less than one. In the manufacture of samples with insulation using non-conductive areas of the substrate, a decrease in insulation resistance was observed as the technological route was performed (after each subsequent operation, the resistance degraded). The degree of degradation can be reduced by reducing the duration of thermal operations. It has been shown that reducing the thickness of the masking oxide causes a decrease in insulation resistance. When using mesa-technology, it is possible to increase the insulation resistance by eliminating the high-temperature oxidation operation and, in fact, due to the absence of a masking coating during phosphorus deposition. Insulation by means of p+-type areas in the gaps between the active elements allows to obtain the highest insulation resistance values. The formation of these regions with a width of 100 μm in the gaps with a width of 200 μm allowed us to obtain an insulation resistance of 25-30 MΩ. To ensure the insulation of the active elements of photodiodes by this method, two thermal operations are added to the technological route. The number of thermal operations can be reduced by doping the entire silicon surface with a low boron concentration before forming a masking coating.