Textured Solar Array

solidex04.in : Textured Solar Array

Requires: Victory Mesh/Victory Device
Minimum Versions: Victory Mesh 1.4.7.R / Victory Device 1.14.1.R
To enhance light absorption, solar cells have been manufactured with textured surfaces. For crystalline silicons, anisotropic etching with enhanced etch rates along preferential low index directions generates complex surface pyramids. This is computationally costly to perform in process simulation.
Alternative simpler geometric etching techniques can be used, yet these require some level of approximation (for instance generating a pyramidal textured surface using angled etch and small box masks to mimic nucleation sites).
An alternative approach is to use solid modeling. The term solid modeling is typically used to describe a class of problems that do not lend themselves easily to etch/depo style simulation. In this example the generation of a textured surface using the Victory Mesh solid modeling commands is demonstrated.
To summarise, the deck begins with a single block of silicon. The aim is to insert a textured horizontal interface in this silicon region.
Two loops have been used within the deck syntax. The inner loop invokes the slice command to intersect a number of pyramids with the silicon block. The material of these pyramids is irrelevant at this stage. The purpose of this intersection is to insert interfaces in the silicon. The pyramid boundaries are used to create slicing planes which intersect the silicon.
Upon completion of the first inner loop, one region above the pyramids, multiple regions inside the pyramids, and one region below are created. Using tag and material the material above the pyramids can be converted to oxide. The merge command will remove interfaces within the silicon. This will result in two regions with a textured interface between them.
The outer loop is used to repeat this process. To cover the textured surface with an anti reflective coating (ARC), a layer of oxide in this example. Each pyramid is translated by an offset equivalent to the oxide thickness. Similar interface in the newly created oxide region are generated. Using a similar approach, the region above the interface can be converted to gas. This will generate a silicon, oxide, gas layered device with a textured interface between each region.
This device is perfectly valid for any remesh scheme. In this case the Delaunay remesh is demonstrated along with some interface refinement within the pyramids. The final device is then imported into Victory Device and a simple ray tracing simulation with a monochromatic light beam place vertically above the surface. Note that most of the photogeneration events take place inside the pyramids texture.