ULVAC to launch thin-film characterization system

TOKYO, JAPAN: ULVAC Inc. has developed and will launch the MPEC-1300 Multi-Probe Evaluation of Thin-Film Characterization system for evaluating thin-film characteristics in the tandem type thin-film solar cell production process.

In the deposition process of solar cell manufacturing, evaluating characteristics such as deposition quality and deposition thickness uniformity is essential to maintain production yields. The evaluation of deposition characteristics, however, has required multiple systems with different measurement principles depending on the purposes, where evaluation samples are required to be prepared for each system, therefore demanding time and manpower.

ULVAC now releases the MPEC-1300 Multi-Probe Evaluation of Thin-Film Characterization System for tandem type solar cell, which can obtain the optical characteristics of Tandem-deposited micro crystal silicone (µc-Si) films in addition to the evaluation of existing amorphous silicone (a-Si) thin-film solar cells, and can also evaluate multiple different film characteristics without preparing sample glass substrates for evaluation use.

Conventional solar cell thin-film characteristics evaluation equipment is used in the production process of a-Si thin-film solar cells to measure the deposition thickness, surface shapes, and resistance of thin films and to control the distribution of materials deposited, deposition quality, and such other elements.

However, destructive evaluation takes place to obtain the optical characteristics, involving the cutting of glass substrates into small pieces and the use of dedicated measuring instruments specialized in this particular measurement. Such equipment has been very ineffective also due to the necessity of introducing multiple measuring instruments, which incur initial costs.

Contrary to this, ULVAC’s newly developed and launched Multi-Probe Evaluation of Thin-Film Characterization System for tandem type solar cell, MPEC-1300, which is compatible with the 5.5th-generation substrate size used as standard for thin-film silicone solar cells, is a breakthrough evaluation system that can evaluate not only a-Si thin films but also the µc-Si crystallinity of tandem type thin-film solar cells, which is achieved by providing a function that can evaluate optical characteristics in addition to the conventional measurement of deposition thickness, surface shapes, and resistance.

The MPEC-1300 Multi-Probe Evaluation of Thin-Film Characterization System for tandem type solar cell has the following conventional measuring functions:
(1) a “Surface Profiler ,” which measures the deposition thickness and in-plane distributions of electrode-use thin films; (2) a “Low-resistance measurement,” which evaluates the resistance distributions of electrode-use metal thin films. In addition, four additional measuring functions have been intergraded including;
(3) a “Raman Spectoscopy ,” which maps in-plane distributions by obtaining µc-Si Crystallinity;
(4) a “Three-dimensional (3D) measurement,” which three-dimensionally evaluates the shapes both of film surfaces after laser scribing and of TCO (Transparent Conductive Oxide) film surfaces;
(5) a “Spectroscopic Ellipsometer,” which evaluates the optical constants of a-Si thin films; and
(6) a “High-resistance measurement,” which evaluates the high-resistance distributions of a-Si thin films.

By including a total of six types of measuring functions, the MPEC-1300 Multi-Probe Evaluation of Thin-Film Characterization System for tandem type solar cell has enabled the thin-film characteristics evaluation of tandem type thin-film solar cells to be performed in one system. In addition, since all surface areas of a glass substrate up to the 5.5th-generation size can be measured with the system, there is no need to destroy substrates for evaluation. These excellent features can greatly reduce initial introduction costs and running costs by about 1/2 compared to when introducing two or more individual dedicated-use measuring instruments.

This evaluation system is designed such that the user can select the measuring functions to be included according to the user’s purpose.

ULVAC is also developing a system for evaluating the distributions of TCO Haze and solar cell local conversion efficiency.