Date of Publication

2025

Document Type

Master's Thesis

Degree Name

Master of Science in Physics

Subject Categories

Physics

College

College of Science

Department/Unit

Physics

Thesis Advisor

Gil Nonato C. Santos

Defense Panel Chair

Wilfred V. Espulgar

Defense Panel Member

Emmanuel T. Rodulfo
Norberto T. Alcantara

Abstract/Summary

The demand for high-performance Vertical-Cavity Surface-Emitting Lasers (VCSELs) operating at a wavelength of 940 nm has significantly increased due to their applications in optical communication, sensing, and consumer electronics. This thesis investigates the wet oxidation process as a viable method for the fabrication of VCSELs, focusing on optimizing this technique to enhance production efficiency and device performance at a mass production scale

The research begins by examining the fundamental operating principles, device structure, and application domains of 940 nm VCSELs, followed by a systematic exploration of the fabrication process, emphasizing epitaxial growth and oxidation techniques crucial for current and optical confinement.

A robust wet oxidation process is developed through optimization of key parameters, including temperature, oxidation time, and nitrogen flow, to achieve precise and reproducible control over oxide aperture size and depth. Post-oxidation characterization is carried out using a combination of optical microscopy (OM), infrared (IR) microscopy, and focused ion beam (FIB) analysis to assess surface quality, aperture uniformity, and cross-sectional morphology. In addition, the oxidation kinetics of high-Al-content AlₓGa₁₋ₓAs layers (x > 0.98) are analyzed to establish a quantitative relationship between aluminum composition and oxidation behavior, enabling rapid in-line feedback for process control.

Finally, to ensure compatibility with mass production requirements, batch-to-batch repeatability and within-wafer uniformity are evaluated. Process control methodologies such as standardized operating procedures (SOP) and statistical process control (SPC) are implemented to maintain oxide aperture dimensions within 9.8 ± 1 μm and wafer-level uniformity below 10%, ensuring high yield and long-term process stability.

This thesis contributes to the broader field of optoelectronics by providing a comprehensive understanding of the wet oxidation process, establishing guidelines for its implementation in mass production while ensuring the optimization of device performance. The findings aim to facilitate advancements in VCSEL technology and its integration into future applications.

Keywords: 940 nm VCSEL, wet oxidation process, mass production

Abstract Format

html

Language

English

Format

Electronic

Keywords

Mass production; Oxidation; Semiconductor lasers

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Embargo Period

8-9-2025

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