DBR low refractive index layer etching method for reducing number of DBR cycles

Abstract

The invention discloses a DBR low refractive index layer etching method for reducing the number of DBR cycles. An ion beam etching method is applied to perform mesoporous etching on the low refractiveindex layer in the DBR layer of a vertical cavity surface emitting laser so as to improve the refractive index difference between the combined two DBR layers. The method is simple in operation and accurate in control and can ensure the size and the accuracy of the obtained mesopore, can realize high reflectivity and can reduce the cycle number of the DBR. In the preparation process of the nano-array device, the focused ion beam etching equipment is applied to perform direct selective etching of the chip. Compared with the dry etching technology, the advantages of the focused ion beam etchingequipment are utilized to reduce the deposition of the protective layer, which can avoid the damage caused by poor accuracy of dry etching, and the radiation damage caused by ion beam etching can alsobe removed by wet etching. The method is simple and controllable and can ensure the size and the accuracy of the obtained mesopore so as to realize DBR with high reflectivity and low cycle number.

Description

technical field [0001] The invention relates to the field of semiconductor lasers, in particular to a DBR low-refractive-index layer etching method for reducing the DBR cycle number. Background technique [0002] In VCSEL, DBR is the key to realize high-performance laser output, and it is also the difficulty of processing. According to the principle of total reflection, the reflective unit must contain materials with two different refractive indices, high and low, and the DBR of the VCSEL must be realized by epitaxial growth on a semiconductor substrate in a lattice-matched manner. This limits the impossibility of epitaxially extending two materials with a large difference in refractive index to achieve the required high reflectivity. Instead, it can satisfy lattice matching, appropriate refractive index difference, and periodically grow alternately with a thickness of λ / (4n ) (n is the refractive index of the grown material) a "reflective stack" of two different semiconduc...

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Problems solved by technology

And the dry etching precision is low, it is difficult to obtain a uniform array of holes

The process parameter window of the electrochemical corrosion method is very small, it is difficult to obtain an array of holes of ideal size, and this method has not yet been maturely applied

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