Wet oxidation process for improving oxidation uniformity of vertical cavity surface emitting laser

Abstract

The invention discloses a wet oxidation process for improving the oxidation uniformity of a vertical cavity surface emitting laser. The oxidation process comprises the following steps: 1, H<2> is introduced before oxidation, pre-treating is performed on the surface of the tablet, and a sheet surface is activated, so the uniformity of subsequent oxidation is facilitated; besides, after the oxidation step is completed, heat preservation continues to be conducted for a period of time, N<2> is continuously introduced till the temperature is reduced to the normal temperature, and oxidation is completed, so that the purpose of continuously introducing N<2> is to remove H<2> in the reaction environment, reduce the passivation effect of H and anneal the wafer; and meanwhile, in the oxidation process, the flow of water vapor is accurately controlled through a liquid flow meter. In addition, the oxidation process can be used for single-sheet oxidation and can also be used for simultaneously carrying out multi-sheet oxidation. The oxidation process provided by the invention can well realize uniform oxidation.

Description

technical field [0001] The invention relates to the field of wet oxidation technology, in particular to a wet oxidation technology for improving the oxidation uniformity of a vertical cavity surface emitting laser. Background technique [0002] A Vertical Cavity Surface Emitting Laser (VCSEL) is a semiconductor laser characterized by emitting laser light perpendicular to the top surface. Its structure is P-type and N-type Bragg reflectors and a resonant cavity sandwiched between them. Both P-type and N-type Bragg mirrors are composed of multi-layer epitaxial wafers to achieve a reflectivity of 99%. In order to achieve a low threshold current, there is usually a high-aluminum layer. Compared with a low-aluminum layer, the high-aluminum layer has a higher oxidation rate under water vapor conditions. After selective oxidation, an aluminum oxide insulating layer is formed, which can Achieving current limitation and optical limitation, which can reduce threshold current and imp...

AI Technical Summary

Problems solved by technology

Depending on the structure, the oxidation depth is between a few microns and more than a dozen microns. It is required that the oxidation depth be precisely and controllable, and the oxidation uniformity and repeatability are relatively good. The uniformity of the traditional oxidation process is difficult to control.

Images