VCSEL fabrication flow

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The market for semiconductor lasers is becoming active as a light source for 3D sensing technologies such as LiDAR, which are required for autonomous driving. As one of them, we will introduce a dry process for VCSELs (Vertical Cavity Surface Emitting Laser), which has merits such as miniaturization and energy saving.

VCSEL fabrication flow

 

1. Epi growth

On a GaAs (gallium arsenide) substrate, AlGaAs / GaAs layers are epigrown as a laminated structure including a DBR (Distributed Bragg Reflector) multilayer film consisting of several tens of pairs or more and an active layer.

 

2. Patterning & Mask forming

Form a mask pattern to form the epi layer into a column called a mesa

 

3. Patterning Mesa

Patterning Mesa by dry etching

Process technology for VCSEL

 

4. Forming active layer & encapsulation

A specific AlGaAs layer designed near the active layer is oxidatively narrowed by wet oxidation (this oxidative narrowing layer is a very important layer that influences the characteristics of the VCSEL as a current and light confinement structure). It also forms a protective film on the side wall of the mesa.

5. Forming electrode

Electrodes are formed on each of the n-type and p-type layers.

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