Etching Process Research Of VCSEL

Vertical-Cavity Surface-Emitting Lasers(VCSEL) have advantages of small divergence angle,short resonator and low threshold current et al, So that the optical information,optical interconnects,and optical fiber coupler has a wide application prospect. The introduction of oxides of restriction technologies to further reduce the device threshold current and improve the electro-optical conversion efficiency, is the current VCSEL optoelectronic device to limit the production to achieve the main technical means used.During pre-oxidation process, Use etching technique to produce oxide window to be exposed oxide layer. Dry etching is the VCSEL production of the more widely used technology, but its high cost and technological complexity of features. We selection the wet etching technology has produced a window because it is low cost,simple and easy to operate, and research the problem of the oxide window. First studied the etching solution for heterogeneous materials, GaAs/AlGaAs selective corrosion characteristics, is particularly concerned about the high-Al oxide layer occurring at the component to be a serious internal corrosion(call "coattail"). Therefor, according to a large number of experimental results, compared and analyzed the corrosion morphology and the orderliness under the same conditions of corrosive solution H₂SO₄/H₂O₂/H₂O, H₃PO₄/H₂O₂/H₂O and H₃PO₄/H₂O₂. Studies have shown that, H₂SO₄/H₂O₂/H₂O solution selective corrosion of materials evident in the material existence of the heterogeneity of the interface step, high-Al composition to be occurring at the inner oxide layer is also more severe corrosion, and the etching rate faster, is not conducive to precise control of etching depth. The etching solution H₃PO₄/H₂O₂ did not have a "coattail" structure, but the sidewall slope is too large (about 45°), and the rate is too slow, for process requirements are more demanding. Focuses on the 980nm/808nm VCSEL wafer wet etching techniques.Under the same conditions we select the H₃PO₄/H₂O₂/H₂O, Because its etching morphology and rates between H₂SO₄/H₂O₂/H₂O and H₃PO₄/H₂O₂ solution. By optimizing the etching solution of the ratio, enhancement of heterogeneous materials non-selective corrosion, both the basic elimination of the "coattail" structure, but also take into account the steepness of the side wall and the etching precision, for the wet etching III - V ethnic heterogeneity of materials provides a meaningful reference.