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Minority carrier lifetime The minority carrier lifetime is one of the most important and significant material parameters. It i Minority carrier lifetime The minority carrier lifetime is one of the most important and significant material parameters. It is extremely sensitive to smallest amounts of impurities or intrinsic defects and hence an ideal parameter for inline characterization of material quality and process control. It is of essential importance for the performance of many semiconductor devices. The minority carrier lifetime is defined as the average time it takes an excess minority carrier to recombine. It is strongly dependent on the magnitude and type of recombination processes in the semiconductor. The main different types of recombination are: SRH recombination ⇒ via defects Auger recombination ⇒ via a three particle process intrinsic or radiative recombination ⇒ via band to band \(\cfrac{1}{\tau_{bulk}} =\cfrac{1}{\tau_{SRH}} + \cfrac{1}{\tau_{Auger}} + \cfrac{1}{\tau_{rad}}\) For silicon SRH is often the dominant recombination mechanism. The minority carrier lifetime in the bulk depends accordingly on the number of defects present and on their recombination properties. In silicon the lifetime can be as high as 1ms, where as in a direct semiconductor as GaAs, where the intrinsic recombination is dominant, the lifetime is only in the range of ns...µs. Besides the defect properties the minority carrier lifetime is dependent on the injection level (excess carrier concentration) and the doping concentration. Figure 1 and 2 display this dependencies for all different lifetimes. Fig. 2: injection dependence of all important recombination rates Fig. 3: doping dependence of all important recombination rates The measured effective lifetime is composed of the bulk lifetime and surface lifetime, which depends on the surface properties of a sample. Hence the surface has to be passivated, if you want to measure the bulk properties of your sample. If you want to investigate the surface passivation quality a FZ-Si wafer is recommendable, because the bulk recombination can be neglected. \(\cfrac{1}{\tau_{eff}} = \cfrac{1}{\tau_{bulk}} + \cfrac{1}{\tau_{surface}}\) Besides that the measured effective lifetime is dependent on the measuring method. For more details read: [1] S. Rein, Lifetime Spectroscopy - A Method of Defect Characterization in Silicon for Photovoltaic Applications, Vol. 85 (Springer, Berlin Heidelberg, 2005) [2] D. K. Schroder, Semiconductor Material and Device Characterization, 2 ed. (John Wiley & Sons, New York, 1998) Matching Products MDP series MDpicts pro High-Resolution, Temperature-Dependent Lifetime Measurement System for Precise Material Characterization Learn more MDP series MDPpro 850+ Advanced Solution for Quality Control of Monocrystalline Silicon Ingots, Bricks, and Wafers Learn more MDP series MDPlinescan Versatile OEM Unit for Lifetime Measurements on Silicon Samples, from Bricks to Processed Wafers Learn more MDP series MDpicts Temperature-Dependent Lifetime Measurement System for Advanced Material Analysis Learn more RES series RESmap High-Precision Resistivity Mapping System for Accurate Material Analysis Learn more MDP series MDPmap Precision Lifetime Charachterization with Exceptional Sensitivity Learn more MDP series MDPspot Quick and Simple Lifetime Measurement Made Easy Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Minority carrier Lifetime maps on 450 mm wafers Since several years, the microelectronic industry is planning to enlarge the wafer size from 300 mm (12 inch) to 450 mm (18 inch) diameter, in order to gain more yield. The technology for the production of such high-quality wafers is now available and only the cost issue of adapting the fabs is still prohibiting the transfer to a larger wafer size. These 450 mm wafers also need to be checked for extrinsic and intrinsic impurities and hence highly spatially resolved lifetime measurements are needed. In cooperation with Fraunhofer IISB , Freiberg Instruments developed a tool for the minority carrier lifetime measurement of 450 mm wafers in the EC-funded project SEA4KET . For the minority carrier lifetime measurement of 450 mm wafers basically the same measurement head as in the MDPmap and MDPpro is used with some adaption for the larger wafer size in the mapping part of the tool. Figure 1 shows one of the first measured lifetime maps of a 450 mm wafer, which clearly shows some handling traces and striations. In figure 2 and 3 the tool, which is situated in the clean room at Fraunhofer IISB is displayed. Fig. 1: minority carrier lifetime map of a 450 mm wafer Fig. 2: Versatile metrology module at Fraunhofer IISB site with implemented minority carrier lifetime measurement head (MDP sensor) in the course of feasibility evaluation activities within SEA4KET project. © Photo: Kurt Fuchs/Fraunhofer IISB Fig. 3: minority carrier lifetime measurement head (MDP sensor) and 450 mm wafer in the course of feasibility evaluation activities within SEA4KET project. © Photo: Kurt Fuchs/Fraunhofer IISB Related Solutions and Industries: Epitaxial Layers & Thin Films Matching Products MDP series MDPpro Advanced Lifetime Measurement System for Quality Control and Material R&D on Semiconductors Learn more MDP series MDPmap Precision Lifetime Charachterization with Exceptional Sensitivity Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Mini-module Classification The PIDcon benchtop system offers fast, cost-effective routine quality control for mini-modules' PID susceptibility, without the need for a climate chamber Potential Induced Degradation (PID) is a critical reliability issue in PV power plants, making it essential to assess products for their susceptibility to PID. The PIDcon system helps manufacturers test products earlier in the production chain, such as mini-modules. The PID in question refers to the shunting of solar cells caused by high-voltage stress-induced leakage currents (PID-s). Mini-modules are contacted at two points, with a contact check ensuring proper connection. The PIDStudi o software allows users to define pass/fail criteria and also provides recommended settings based on IEC standards and the expertise of Fraunhofer CSP scientists. Matching Products PID series PIDcon bifacial Quality Control Solution for Bifacial PERC/PERC+, HIT, Topcon, c-Si Solar Cells, Mini Modules, and More Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Microwave detected photoconductivity The advanced method MDP is suited for defect investigation and mapping of wafers and ingotsWith its extraordinary sensitivity, resolution and speed MDP enables injection dependent measurements as well as mapping with a very high resolution. The novel method MDP is well suited for both, defect investigation by e.g. injection dependent minority carrier lifetime measurements, as well as mapping of wafers or even bricks for inline metrology. It exceeds his competitors µPCD (microwave detected photoconductivity decay) and QSSPC (quasi steady state photo conductance) in terms of sensitivity, resolution and speed. The photoconductivity, which is closely related to the diffusion length is measured by microwave absorption during and after the excitation with a rectangular laser pulse. Figure 1 displays the measurement principle for MDP and MD-PICTS measurements. generation of free carriers traps are filled with carriers recombination of free carriers thermal reemission of trapped carriers temporally shifted recombination of reemitted carriers A microwave with about 10 GHz is generated in a frequent stable microwave-generator and split into a reference and measurement part. With an attenuator the power can be adjusted and ranges typically from 1 to 100 MW. The sample is situated just outside the cavity and is part of the measurement system. A special iris in the cavity-wall allows the microwave field to penetrate the sample. Thus, the complex dielectric constant of the sample influences the resonant frequency and the loss properties of the cavity. Microwave absorption by excess charge carriers is detected with an IQ-detector. The sample is placed on an x-y-table, allowing theoretically every sample size and to move the sample in the x-y-plane. For temperature dependent MD-PICTS measurements the sample has to be part of a cryostat system, so that the sample size is currently limited, but apart from that it is principally the same measurement system. Fig. 1: Energy scheme of the measurement principle Fig. 2: Exemplary signal Fig. 3: setup for MDP and MD-PICTS The high detection sensitivity enabled by this technique allows the application even of weak laser pulses with an intensity of µW to mW and with unlimited pulse duration. Hence it is possible to measure in a non- or steady state regime and to continously vary the pulse length from 100 ns to several ms. The resolution of this system is only limited by the diffusion length of the sample. Besides advantages in speed and sensitivity, a major advantage of MDP is the ability to measure photoconductivity and minority carrier lifetime simultaneously. Accordingly more parameters can be extracted from each measurement, like diffusion length, mobility and even trapping dynamics. Fig. 4: Exemplary lifetime map of a mc-Si wafer Fig 5: Exemplary photoconductivity map of a mc-Si wafer Matching Products MDP series MDPmap Precision Lifetime Charachterization with Exceptional Sensitivity Learn more MDP series MDPspot Quick and Simple Lifetime Measurement Made Easy Learn more MDP series MDpicts pro High-Resolution, Temperature-Dependent Lifetime Measurement System for Precise Material Characterization Learn more MDP series MDPpro 850+ Advanced Solution for Quality Control of Monocrystalline Silicon Ingots, Bricks, and Wafers Learn more MDP series MDPlinescan Versatile OEM Unit for Lifetime Measurements on Silicon Samples, from Bricks to Processed Wafers Learn more MDP series MDpicts Temperature-Dependent Lifetime Measurement System for Advanced Material Analysis Learn more RES series RESmap High-Precision Resistivity Mapping System for Accurate Material Analysis Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Microwave Detected Photoconductivity Unlock material insights with µPCD/MDP(QSS) – High-resolution, contactless measurement solutions for research and production: The MDP series Visualization of semiconductor quality is achieved by widely advanced microwave techniques. Which allow for a mapping of key electrical semiconductor parameters contactless and with production speed. Measurement of parameters like minority carrier lifetime, photoconductivity, resistivity and defect information can be mapped by a so far unsurpassed combination of spatial resolution, sensitivity and measurement speed. From OEM modules to turnkey systems, the MDP series adapts to your workflow – empowering your next innovation in microelectronics and photovoltaics. MDP series MDPmap Learn more MDP series MDPspot Learn more MDP series MDpicts pro Learn more MDP series MDPpro 850+ Learn more MDP series MDPlinescan Learn more MDP series MDpicts Learn more MDP series MDPpro Learn more MDP series HTpicts Learn more Discover more of the MDP series Applications Learn more Technology Learn more Software Learn more Publications Learn more Seamlessly transition from lab research to full-scale production with our advanced “Lab to Fab” electrical characterization equipment. Dr. Nadine Schüler Head of Research & Development Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Microwave Detected Photo Induced Current Transient Spectroscopy (MD-PICTS) is a modification of MDP, where temperature dependent measurements of the defect part of the transient are accomplished. In order to investigate defects in semiconductors it is widely spread to use temperature dependent methods as deep level transient spectroscopy (DLTS). Usually for these methods it is necessary to form contacts on the samples, which means the sample itself is often altered due to annealing steps. Furthermore for lot of semiconductors some effort is needed to create ohmic contacts at all. MD-PICTS is a non-destructive, contactless method with which the activation energies and capture cross sections of defects can be determined with a high accuracy. For MD-PICTS measurements the photoconductivity of a sample after the irradiation with light is measured with a resonant microwave cavity. For the determination of the activation energy the temperature dependent change of the photoconductivity transient is determined via a window analysis, which is also used for DLTS measurements (fig. 1). Fig.2 shows a so called MD-PICTS spectrum which results from the window analysis. Every peak in this spectrum is a certain defect in the sample. The temperature shift of the maximum of this peak is plotted in an Arrhenius plot according to this formula of the emission rate: \(e_{n} = \gamma\delta_{n}T^{2}e^{-\frac{E_{A}}{kT}}\) From the slope of the Arrhenius plot (Fig. 3) the activation energy can be determined. With the novel commercially available MD-PICTS equipment it is possible to measure the temperature dependence of the photoconductivity transient in a range from 20…500 K. In the past Si, GaAs, InP, SiC and many more semiconductors have already been successfully investigated with this method. For more information please read: [1] B. Berger, N. Schüler, S. Anger, B. Gruendig-Wendrock, J. R. Niklas, K. Dornich, physica status solidi A, 1-8 Fig. 1: Depiction of the window analysis of the photoconductivity transient Fig. 2: resulting MD-PICTS spectrum Fig. 3: Arrhenius plot Fig. 4: example of a MD-PICTS spectrum of different tempered Cz—Si wafers Related Solutions and Industries: Epitaxial Layers & Thin Films Matching Products MDP series HTpicts Advanced High-Temperature Lifetime Measurement System for In-Depth Material Analysis Learn more MDP series MDpicts pro High-Resolution, Temperature-Dependent Lifetime Measurement System for Precise Material Characterization Learn more MDP series MDpicts Temperature-Dependent Lifetime Measurement System for Advanced Material Analysis Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Medical dosimetry Radiotherapy, diagnostic radiology, nuclear medicine Medical dosimetry Ionizing radiation from a large variety of isotopic sources, as well as accelerators, electron beams, etc. are increasingly used in radiotherapy. Clinical diagnostics employing ionizing radiation (mainly X-ray) is expanding. Such uses require monitoring of exposures as well as determination of the delivered doses which can be achieved by luminescence dosimetry. Thermoluminescence (TL) dosimetry Photostimulated Luminescence (PSL or POSL) or Optically Simulated Luminescence (OSL) AlO, BeO, LiF, CaF, CaSO, … Life/real-time monitoring by radiofluorescence (e.g. Al 2 O 3 :C, BeO) Simultaneous life and accumulated dose measurement (OSL) Spatial measurement of dose distribution with OSL Nascimento LF, Vanhavere F, Boogers E, Vandecasteele J & De Deene Y (2014) Medical dosimetry using a RL/OSL prototype. Radiation Measurements 71, 359-363. Depth dose distribution for 6 MeV measured with radiofluorescence of Al2O3:C (from Nascimento et al., 2014) Matching Products TL/OSL series lexsygsmart The most sensitive TL/OSL reader Learn more TL/OSL series TLDcube A modern TLD reader by Freiberg Instruments Learn more TL/OSL series lexsygresearch The most advanced TL/OSL reader Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Materials Any photoactive material from raw material to finished device: From powder-based samples over wafers to boules or ingots. From 10 x 10 mm 2 and up to 300 mm diameter From titanium dioxide over silicon and to aluminium nitride (1000+ materials) Matching Products SPS/SPV series HR-SPSmap with fixed energy excitation sources High-Resolution and Sensitive Surface Photovoltage Measurement Solutions Learn more SPS/SPV series HR-SPSmap with variable energy excitation source with a variable energy excitation source Learn more DPM series DPM100 Wide range double prism monochromator Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Materials Electrical properties and defects of a large variety of semiconductor materials, devices and dielectric materials can be investigated contact less and destruction free with our advanced method MDP. Electrical properties and defects of a large variety of semiconductor materials, devices and dielectric materials can be investigated contact less and destruction with our advanced method MDP. MDP is a contact less and destruction free method, so that no sample preparation is needed. The only exception is that for investigations of the bulk properties of for example silicon samples a surface passivation is preferred. There are no restrictions on the sample shape or size starting with nano material powders up to 12" wafers. Apparently all semiconductors on the market can be investigated. Starting with a variety of electronic grade- and multicrystalline silicon. Due do the high sensitivity even the quality of thin epitaxial layers and strained silicon can be characterized. Investigations have been carried out on GaAs, InP, SiC, GaN, Ge and other compound semiconductors. The list is constantly expanding. So far few limitations are known. Matching Products MDP series MDPmap Precision Lifetime Charachterization with Exceptional Sensitivity Learn more MDP series MDPspot Quick and Simple Lifetime Measurement Made Easy Learn more MDP series MDpicts pro High-Resolution, Temperature-Dependent Lifetime Measurement System for Precise Material Characterization Learn more MDP series MDPpro 850+ Advanced Solution for Quality Control of Monocrystalline Silicon Ingots, Bricks, and Wafers Learn more MDP series MDPlinescan Versatile OEM Unit for Lifetime Measurements on Silicon Samples, from Bricks to Processed Wafers Learn more MDP series MDpicts Temperature-Dependent Lifetime Measurement System for Advanced Material Analysis Learn more RES series RESmap High-Precision Resistivity Mapping System for Accurate Material Analysis Learn more Get in touch Do not hesitate to contact us – we are available to assist you with any inquiries or requests. Use our inquiry tool or reach out via email: sales @ freiberginstruments.com

Martin Ferkinghoff Head of Service Freiberg Instruments is the right place for you if you enjoy achieving milestones as part of a team, remain curious and have a desire for change. Martin Ferkinghoff Head of Service Since April 2023, Martin has headed the Freiberg Instruments service department and ensures that all of our partners' devices work perfectly. His mission: to solve customer problems quickly and actively prevent them. Martin, what was your first point of contact with FI? Before I joined #TeamFI, I was responsible for the external training of apprentices in the Freiberg region - including the mechatronics engineers at Freiberg Instruments. I liked the spirit and drive of the company and quickly had the feeling that it could be a good match for me. What do you associate with our guiding principle “Driven by Innovation”? Always questioning achieved goals. Freiberg Instruments is the right place for you if you enjoy achieving milestones as part of a team, remain curious and have a desire for change. What else do you want to achieve with FI in the future? As “Pinky and the Brain” have already said: We want to take over the world (in measurement technology). ? What are you particularly proud of? There is nothing that I would like to explicitly emphasize. I love solving problems as part of a team. Every day brings new challenges and I'm proud of every task I solve. The biggest challenge in your job? Completing a wide range of tasks while keeping an eye on all expectations. This is only possible with a solution-oriented way of working. What is your balance to your job? I clear my head in the water - I'm a passionate swimmer. Apart from that, I ride my motorcycle and love working on Trabants. How does FI support your professional development? In my case: by giving me a lot of freedom. Martin ist Driven by Innovation Let's drive innovation together Current job openings Get to know the team Dr. Viktoriia Nikonova Productmanager Surface Photovoltage Spectroscopy Learn more Dr. Christian Hagendorf Projekt- & Key Account Manager XRD Series Learn more Marcus Richter Application & Service Engineer XRD Learn more Burkhard Winkler Senior Sales Engineer for semiconductors and automation Learn more Diana Trinks Assistant to the management Learn more Marcus Göhler Head of Electronics Development Learn more Thanga Kumar Global Sales Director Learn more Dr. Nadine Schüler Head of Research and Development Learn more