Method of fabricating semiconductor device

Abstract

A method of fabricating a semiconductor device includes a step of growing at least one tapered epitaxial layer upon a supporting surface by chemical beam epitaxy, the plane of the taper being inclined to the supporting surface.

Description

technical field [0001] The invention relates to a method for manufacturing a semiconductor device with a tapered epitaxial layer. Background technique [0002] Optoelectronic systems include optical fibers and optoelectronic semiconductor devices such as lasers, amplifiers, modulators, detectors, and switches. The size and shape of the optical modes supported by optical fibers are very different from those in opto-semiconductor devices, leading to mode mismatches and high optical loss. [0003] One technique that can reduce this optical loss is to place a microlens between the optoelectronic semiconductor device and the optical fiber. Microlenses can change the size of the optical mode output of an optoelectronic semiconductor device or optical fiber, but will not change the shape of the optical mode. Another technique is to place an optical mode conversion waveguide between the optoelectronic semiconductor device and the optical fiber. Both technologies require very hig...

AI Technical Summary

Problems solved by technology

First, the entire process is complex and time-consuming

Second, removal of the partially grown wafer from the growth apparatus and etching of the waveguide core can contaminate the waveguide, increasing optical loss and reducing yield

Third, the reproducibility of these methods is very low

This technique includes additional growth steps for dielectric aperture growth and additional processing steps to remove the dielectric aperture, as well as processing for patterning the aperture, which introduces significant delays and can contaminate the surface

Although mechanical orifice plates can be used to replace dielectric orifice plates, MOVPE growth inevitably leads to composition inhomogeneity in the tapered layer due to the different diffusion lengths of reactant gases in MOVPE growth.

This makes the index of refraction non-uniform within the tapered layer, which adversely affects light guiding within the layer

Also, wafers are exposed to air during aperture plate insertion and removal, resulting in contamination of wafers

Another disadvantage is the deposition of material on the orifice plate, which needs to be cleaned or replaced

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