Proceedings PaperInGaAs/InP Photodetectors For Fiber Optic Applications
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InGaAs photodiodes for detection in the 1.0 to 1.7 µm spectral region are now widely used in fibre optics and other applications. Properties, performance characteristics, and fabrication parameters for diodes grown by both Vapour-phase a1d6 Liquid-Phase-Epitaxial techniques have been described in a number of published reports . It is the purpose of this paper to present some recent results from a number of device types fabricated using Vapour-Phase-Fpitaxial-Growth techniques. The structure is shown in Figure 1. Successive layers of n- In.53Ca.47As (nominally undoped) and p+ InP are grown on a low-dislocation-density n-type InP substrate. Diffusion of zinc from the p+ InP layer results in the formation of a p-n junction in the InGaAs layer, about 1-2μm below the InP layer. The p+-InP serves as a passivation-layer for the InGaAs surface, and is transpa-rent for wavelengths above about 1pm. Standard photolithographic techniques are used to define p-side contacts (evaporated AuZn), and to mask for etching of the mesa. Deposited silicon dioxide has been used as an anti-reflection coating. The use of a Cr-Au metallization on the lower surface of the substrate has made it possible to solder the diode chips onto an appropriate carrier.