Contact Resistivity and Sheet Resistance TLM-SCAN+
The contact resistance before metallization is an important contribution to the total series resistance of screen-printed solar cells. The transfer length method with a suitable test structure is the best way to separate the contact resistance from other series resistance effects. However, the contact resistance can vary significantly across a solar cell, so methods are needed to measure it with spatial resolution on the finished solar cell. TLM-SCAN produces a map of the contact resistivity of a solar cell that has been cut into stripes with a laser or a dicing saw.

The map on the right demonstrates the resolution and repeatability, as it shows the same band measured 14 times.

Contact resistivity meter

This compact instrument measures contact resistivity, finger line resistance, finger width and finger height of finished solar cells or test structures.

By electrifying all axes, maps for all of these approaches can be created with the push of a button.

Four-point probe for measuring sheet resistance of thin diffusion layers and wafer resistivity makes the TLM-SCAN a low-cost, fast, high-quality four-point probe mapper.

Features that make operation easier:
Automatic position correction for best contact quality
Automatic start when lid is closed
Automatic sampling number
Software probe identification
Precise navigation with joy stick and microscope camera
Probe and remeasure single points by clicking on the image

Multifunctional solar cell grid line contact resistance tester

The quality of the surface metal ohmic contact of crystalline silicon solar cells is reflected by the contact resistance. In the optimization of solar cell electrodes, contact resistance is an important aspect that needs to be considered. The size of the contact resistance is not only related to the contact pattern, but also to the diffusion process and the contact formation process. The quality of the ohmic contact of different grid line patterns can be reflected by the size of the contact resistivity. Therefore, the problems existing in the processes such as diffusion, electrode production and sintering can be reflected through the study and calculation of the contact resistivity. However, the current measurement method has the defects of long measurement time, low efficiency and poor accuracy, and at the same time there is a lack of a test equipment specifically for measuring the contact resistance of solar cells, which is not conducive to the application of solar cell contact resistance measurement on the production line. This technical achievement uses the TLM method to measure the contact resistance, and combined with the motor platform, camera and computer control technology, it can basically realize the functions of automatic measurement and result analysis and calculation.

Market forecast: This technology can be applied to battery manufacturers, silver paste manufacturers and other enterprises related to battery grid line technology, so as to quickly measure the grid line contact resistance and improve the process. There are no mature products of this kind at present. If they can be developed and industrialized as soon as possible, the products developed by this technology will have a head start in the market. At present, the laboratory has prepared a prototype that can be used, and some silver paste manufacturers have tried it and used the measurement results as a reference to improve the product.
Batch mode for multiple TLM test patterns on one sample
Sequence mode measures contact resistivity and mapping of finger geometry with the push of a button

Contact resistivity and more

Contact resistivity and sheet resistance

The contact resistance of the front metallization is an important contribution to the total series resistance of screen-printed solar cells. The transfer length method with a suitable test structure is the best method to separate the contact resistance from other series resistance effects. However, the contact resistance may vary considerably over the solar cell so a method to measure it with spatial resolution on the finished solar cell is necessary. The TLM-SCAN creates mappings of the contact resistivity of a solar cell that is cut into stripes with a laser or a dicing saw.

The mapping on the right demonstrates the resolution and repeatabilty as it shows the same stripe measured 14 times.