Surface-illuminated photon-trapping high-speed Ge-on-Si photodiodes with improved efficiency up to 1700  nm

Cansizoglu, Hilal; Bartolo-Perez, Cesar; Gao, Yang; Devine, Ekaterina Ponizovskaya; Ghandiparsi, Soroush; Polat, Kazim G.; Mamtaz, Hasina H.; Yamada, Toshio; Elrefaie, Aly F.; Wang, Shih-Yuan; Islam, M. Saif

doi:10.1364/prj.6.000734

Cited by 59 publications

(40 citation statements)

References 45 publications

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“…[ 1,28 ] Using this approach, ultrafast and highly sensitive PDs have been demonstrated by several groups both for short [ 24,25,29–31 ] and longer wavelengths. [ 26,32–35 ] However, due to the different degrees of freedom for design and fabrication, the implementation of PT structures in PDs remains a challenge. Extensive design variations can be analyzed by numerical methods to optimize the performance of the device.…”

Section: Introductionmentioning

confidence: 99%

Maximizing Absorption in Photon‐Trapping Ultrafast Silicon Photodetectors

Bartolo-Perez

Qarony

Ghandiparsi

et al. 2021

Advanced Photonics Research

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Silicon photodetectors (PDs) operating at near‐IR wavelengths with high speed and high sensitivity are becoming critical for emerging applications, such as light detection and ranging (LIDAR) systems, quantum communications, and medical imaging. However, such PDs present a bandwidth‐absorption trade‐off at those wavelengths that have limited their implementation. Photon‐trapping (PT) structures address this trade‐off by enhancing the light–matter interactions, but maximizing their performance remains a challenge due to a multitude of factors influencing their design and fabrication. Herein, strategies to improve the PT effect while enhancing the speed of operation are investigated. By optimizing the design of PT structures and experimentally integrating them in high‐speed PDs, a simultaneous broadband absorption efficiency enhancement up to 1000% and a capacitance reduction of more than 50% are achieved. Empirical equations correlate the quantum efficiency of PDs with the physical properties of the PT structures, material characteristics, and limitations of the fabrication technologies. The results that are obtained open routes toward designing cost‐effective complementary metal–oxide‐semiconductor (CMOS)‐integrated receivers.

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Section: Introductionmentioning

confidence: 99%

Maximizing Absorption in Photon‐Trapping Ultrafast Silicon Photodetectors

Bartolo-Perez

Qarony

Ghandiparsi

et al. 2021

Advanced Photonics Research

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“…Our recent experimental studies [27,28] showed that an array of nanoholes integrated on a 2-μm-thick Si film effectively traps light with wavelengths between 800 and 950 nm and can be used to achieve a high EQE (40-60%) in Si photodetectors while ensuring ultrafast impulse response (full-width at half-maximum) of 30 ps. High-speed Geon-Si photodiodes with photon-trapping holes have also been demonstrated with improved EQE at wavelengths between 1200 and 1800 nm [29]. Light-trapping properties of such hole arrays in Si were investigated by finitedifference time-domain method [27] and the effects of hole shape and tapering angle of funnel-shaped holes on the EQE of the photodiodes were analyzed and discussed in detail [27,28].…”

Section: Introductionmentioning

confidence: 99%

Rigorous coupled-wave analysis of absorption enhancement in vertically illuminated silicon photodiodes with photon-trapping hole arrays

et al. 2019

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In this paper, we present a rigorous coupled-wave analysis (RCWA) of absorption enhancement in all-silicon (Si) photodiodes with integrated hole arrays of different shapes and dimensions. The RCWA method is used to analyze the light propagation and trapping in the photodiodes on both Si-on-insulator (SOI) and bulk Si substrates for the datacom wavelength at about 850 nm. Our calculation and measurement results show that funnel-shaped holes with tapered sidewalls lead to low back-reflection. A beam of light undergoes a deflection subsequent to the diffraction in the hole array and generates laterally propagating waves. SOI substrates with oxide layers play an important role in reducing the transmission loss, especially for deflected light with higher-order diffraction from the hole array. Owing to laterally propagating modes and back-reflection on the SiO2 film, light is more confined in the thin Si layer on the SOI substrates compared to that on the bulk Si substrates. Experimental results based on fabricated devices support the predictions of the RCWA. Devices are designed with a 2-μm-thick intrinsic layer, which ensures ultrafast impulse response (full-width at half-maximum) of 30 ps. Measurements for integrated photodiodes with funnel-shaped holes indicate an enhanced external quantum efficiency of more than 55% on the SOI substrates. This represents more than 500% improvement compared to photodiodes without integrated phototrapping nanoholes.

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“…where a Ge = 0.56578 nm, and Poisson's ratio υ = 0.271. The compressive or tensile strain R of the Ge film can be calculated by the following equation [22]: R = a Ge − a Si a Ge − a Si (3) where the Si lattice constant is a Si = 0.5431 nm. When the strain relaxation R = 1, there is no stress in the Ge film; when R < 1, there is compressive stress; and when R > 1, there is tensile stress.…”

Section: Results and Analysismentioning

confidence: 99%

“…The high near-infrared absorption property of Ge material has been widely used in III-V multijunction solar cells and photodetectors [1][2][3][4]. However, it is expensive to fabricate III-V solar cells on 100-µm-thick Ge substrates.…”

Section: Introductionmentioning

confidence: 99%

Effect of Substrate Biasing on the Epitaxial Growth and Structural Properties of RF Magnetron Sputtered Germanium Buffer Layer on Silicon

2021

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High-quality single-crystal-like Ge (004) thin films have been epitaxially grown using radio-frequency magnetron sputtering on Si (001) substrates successfully. The crystalline quality of the Ge films can be obviously improved by applying a positive bias on the substrate holder. X-ray diffraction measurements show that the single-crystal-like Ge film has a narrow full width at half maximum of 0.26°. The perpendicular lattice constant (aGe⊥) and in-plane lattice constant (aGe∥) are 0.5671 and 0.564 nm. The Raman shift full width at half maximum shows that the defects in the film are obviously reduced. Transmission electron microscopy diffraction patterns also show that the Ge (004) film has good crystalline quality. The results can be applied as Ge buffer layers on Si substrates for the fabrication of high-efficiency III–V solar cells and photodetectors.

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Surface-illuminated photon-trapping high-speed Ge-on-Si photodiodes with improved efficiency up to 1700 nm

Cited by 59 publications

References 45 publications

Maximizing Absorption in Photon‐Trapping Ultrafast Silicon Photodetectors

Maximizing Absorption in Photon‐Trapping Ultrafast Silicon Photodetectors

Rigorous coupled-wave analysis of absorption enhancement in vertically illuminated silicon photodiodes with photon-trapping hole arrays

Effect of Substrate Biasing on the Epitaxial Growth and Structural Properties of RF Magnetron Sputtered Germanium Buffer Layer on Silicon

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