Performance of AlGaInP LEDs on silicon substrates through low threading dislocation density (TDD) germanium buffer layer

Abstract

Performance of GaInP/AlGaInP multi-quantum wells light-emitting diodes (LEDs) grown on low threading dislocation density (TDD) Germanium-on-Silicon (Ge/Si) substrates are compared and studied. Three approaches are used to realize the low TDD Ge/Si substrates. The first approach is the two-step growth of Ge/Si substrate with TDD of ∼5×10 7 cm −2 . The second approach is through doped the Ge seed layer with arsenic (As) and TDD of <5×10 6 cm −2 can be achieved. The third approach is through wafer bonding and layer transfer techniques, germanium-on-insulator (GOI) substrate with TDD of ∼1.2×10 6 cm −2 can be fabricated. To demonstrate the quality of these Ge/Si substrates, LEDs fabricated on commercially available Ge/Si and bulk Ge substrates were also included for comparison purposes. The LEDs fabricated on the As-doped Ge/Si and GOI substrates exhibit superior performances, with output light intensity at least 2× higher compared to devices fabricated on commercially available Ge/Si substrate. These findings enable the monolithic integration of visible-band optical sources with Si-based control circuitry.

III-V Heterostructure Grown on 300mm Ge/Si Wafer for Large-Scale Fabrication of Red μ-LEDs

“…Following the same growth procedure as in [10], [11], we obtain a superior quality Ge buffer layer with state-of-the art characteristics [9]: a roughness of ~0.8nm quantified by atomic force microscopy (AFM) as well as a TDD of ~10 7 cm -2 evaluated by electron channeling contrast imagery (ECCI). Subsequently, the AlGaAs-based heterostructure, designed to reach its peak emission wavelength at ~650nm, is grown on the so-formed Ge/Si 300mm wafer in an Applied Materials MOCVD 300 mm cluster tool.…”

“…Due to the large lattice mismatch between Si and GaAs (4.1%), a direct growth of those epilayers on large-scale Si wafers leads to a high threading dislocation density (TDD), which decreases the brightness of the resulting devices [6]. Recent works however suggest that they are different routes to alleviate this issue [7], [8], among which the use of Ge layer, which we will focus in this work [9]. However, to the best of our knowledge, this has not been achieved yet on large-scale 300mm silicon wafers.…”

Dark current analysis of germanium-on-insulator vertical p-i-n photodetectors with varying threading dislocation density

“…11 Furthermore, a germanium-on-insulator (GOI) substrate has been demonstrated with TDD as low as ∼10 6 cm −2 via direct wafer bonding (DWB) and layer transfer followed by the oxygen (O 2 ) annealing process, taking advantages of wafer-scale fabrication and back-end-of-line (BEOL) integration. 12,13 However, the dark current study on such low TDD Ge photodetectors is still lacking.…”

Using SiO2-Based Distributed Bragg Reflector to Improve the Performance of AlGaInP-Based Red Micro-Light Emitting Diode

“…1,3 In this regard, the chipsize dependence of the output performance of blue, green, and red LEDs has been actively characterized. [11][12][13][14][15][16][17] On the one hand, for mass-production, the fabrication of p-side-up micro-LEDs with horizontal electrode structures are beneficial. Thus, flip-chip and lateral-geometry p-side-up AlGaInP-based red-LEDs have been widely investigated but their performance was found to be further improved considerably.…”