High-Efficiency p-i-n Photodetectors on Selective-Area-Grown Ge for Monolithic Integration

Abstract

Cataloged from PDF version of article.We demonstrate normal incidence p-i-n photodiodes\ud on selective-area-grown Ge using multiple hydrogen annealing\ud for heteroepitaxy for the purpose of monolithic integration. An\ud enhanced efficiency in the near-infrared regime and the absorption\ud edge shifting to longer wavelength is achieved due to 0.14% residual\ud tensile strain in the selective-area-grown Ge. The responsivities\ud at 1.48, 1.525, and 1.55 μm are 0.8, 0.7, and 0.64 A/W, respectively,\ud without an optimal antireflection coating. These results are\ud promising toward monolithically integrated on-chip optical links\ud and in telecommunications

High quality single-crystal germanium-on-insulator on bulk Si substrates based on multistep lateral over-growth with hydrogen annealing

“…5,6 Even more research efforts are directed toward the realization of on-chip optical signaling using Ge-based devices. There has been a surge in interest in SiGe based optoelectronics such as near IR detectors, [7][8][9] Ge-based integrated optical modulators, 10,11 and so on. The marriage of microelectronics to high performance photonics requires precise control and process compatibility.…”

Suspended germanium membranes photodetector with tunable biaxial tensile strain and location-determined wavelength-selective photoresponsivity

“…24,25 For these works, the strain was controlled from the nanowire size, and the fabrication process is complex as compared to our method. 24,25 The absorption coefficient (α) of the Ge membrane on different position could be extracted as follow, 6,26 the photodiode during the photocurrent measurements, the light could be considered propagating in silica/SiO2 layers before reaching the Ge layer. Thus, by assuming the interface between the SiO2 layer and the tip of the fiber is lossless, surface reflectivity (r) could be calculated by the Fresnel relation: 𝑟 = , where n1 and n2 are the refractivity of SiO2 and Ge, respectively.…”

High Performance p-i-n Photodetectors on Ge-on-Insulator Platform

“…The GOI PDs exhibited ultra-low dark current because of the absence of a defective region compared to Ge-on-Si PDs. The dark current density (J total ) can be divided into the bulk leakage current density (J bulk ) and the surface leakage density (J surf ) using the following equation [6]:…”

“…The J surf of 0.37 µA/cm indicates excellent surface passivation, resulting in lower surface leakage current. The dark current density (Jtotal) can be divided into the bulk leakage current density (Jbulk) and the surface leakage density (Jsurf) using the following equation [6]:…”

“…For high-quality Ge epitaxy on Si, the greatest challenge is the 4.2% lattice Nanomaterials 2021, 11, 1125 2 of 11 mismatch ratio between these two elements. This mismatch will result in high surface roughness after growth and high threading dislocation densities in the Ge epitaxial layer, which will hinder the integration of Si and Ge devices and affect device epitaxy on Si [4][5][6]. SiGe buffer layers were used to reduce the number of threading dislocations in the Ge layer.…”