Key figures

^{The gross value was used this year for Scope 2.1 emissions “electricity” (location-based). The values from the previous year in this category were adjusted accordingly and also shown in gross terms. Scope 3.8-3.10 and 3.13-3.15 do not apply to AIXTRON. A separate statement of Scope 3.9 is not possible due to the data situation. Basically, the values were calculated based on consumption or determined quantities.}

^{The value-based approach was chosen in Scope 3.1 for the areas of health/social services, service/consulting and software, as it is not possible to express the data in kilograms for these categories. Instead, metrics based on euro values were used to represent the relevant information.}

^{The quantities in Scope 3.11 in kWh refer to a life cycle of the machines of 10 years.}

GRI Content Index

 Template: Proportion of turnover from products or services associated with Taxonomy-aligned economic activities – disclosure covering year 2023

^{Yes, taxonomy-eligible and taxonomy-aligned activity with the relevant environmental objective / N - No, taxonomy-eligible but not taxonomy-aligned activity with the relevant environmental objective / N/EL - not eligible, taxonomy-ineligible activity for the relevant environmental objective}

Template: Proportion of CapEx from products or services associated with Taxonomy- aligned economic activities – disclosure covering year 2023

Reporting form 1: Activities in the fields of nuclear energy and fossil gas

Template 1 Nuclear and fossil gas related activities

Prüfungsvermerk des unabhängigen Wirtschaftsprüfers

An die Aixtron SE, Herzogenrath

Wir haben die für die AIXTRON SE, Herzogenrath (im Folgenden „Aixtron“) zusammengefasste nichtfinanzielle Konzernerklärung für den Zeitraum vom 1. Januar bis

31. Dezember 2023, enthalten im Nachhaltigkeitsbericht von Aixtron und dort gekennzeichnet mit einem „Ω“, (im Folgenden „Bericht“), einer betriebswirtschaftlichen Prüfung zur Erlangung begrenzter Sicherheit unterzogen.

Independent assurance practitioner's report

To AIXTRON SE, Herzogenrath

We have performed a limited assurance engagement on the combined consolidated non- financial statement of AIXTRON SE, Herzogenrath (hereinafter, “AIXTRON”), for the period from January 1, 2023 to December 31, 2023 (hereinafter, the “consolidated non- financial statement” or “NFS”). The consolidated non-financial statement is included in the separate AIXTRON sustainability report 2023 and consists of the disclosures marked therein with an omega sign ("Ω").

Responsibilities of Management

Management of AIXTRON is responsible for the preparation of the consolidated non- financial statement in accordance with Sections 315c in conjunction with 289c to 289e HGB [“Handelsgesetzbuch”: German Commercial Code] and Article 8 of REGULATION (EU) 2020/852 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 18. June 2020 on the

establishment of a framework to facilitate sustainable investment, and amending Regulation (EU) 2019/2088 (hereinafter the “EU Taxonomy Regulation”) and the Delegated Acts adopted thereunder, as well as for making their own interpretation of the wording and terms contained in the EU Taxonomy Regulation and the delegated acts adopted thereunder as set out in section „EU Taxonomy” of the consolidated non- financial statement.

This responsibility includes the selection and application of appropriate non-financial reporting methods and making assumptions and estimates about individual non-financial disclosures of the group that are reasonable in the circumstances. Furthermore, management is responsible for such internal control as they consider necessary to enable the preparation of a consolidated non-financial statement that is free from material misstatement, whether due to fraud or error.

The EU Taxonomy Regulation and the Delegated Acts issued thereunder contain wording and terms that are still subject to considerable interpretation uncertainties and for which clarifications have not yet been published in every case. Therefore, management has disclosed their interpretation of the EU Taxonomy Regulation and the Delegated Acts adopted thereunder in section „EU Taxonomy“ of the consolidated non-financial statement. They are responsible for the defensibility of this interpretation. Due to the immanent risk that indeterminate legal terms may be interpreted differently, the legal conformity of the interpretation is subject to uncertainties.

1 The English language text below is a translation provided for information purposes only. The original

German text shall prevail in the event of any discrepancies between the English translation and the German original. We do not accept any liability for the use of, or reliance on, the English translation or for any errors or misunderstandings that may arise from the translation.

Independence and Quality Assurance of the Assurance Practitioner’s firm

We have complied with the independence and quality assurance requirements set out in the national legal provisions and professional pronouncements, in particular the Professional Code for German Public Auditors and Chartered Accountants (in Germany) and the IDW Standard on Quality Management 1: Requirements for Quality Management in Audit Firms (IDW QMS 1 (09.2022)).

Responsibility of the Assurance Practitioner

Our responsibility is to express a conclusion with limited assurance on the consolidated non-financial statement based on our assurance engagement.

We conducted our assurance engagement in accordance with International Standard on Assurance Engagements (ISAE) 3000 (Revised): "Assurance Engagements other than Audits or Reviews of Historical Financial Information" issued by the IAASB. This standard requires that we plan and perform the assurance engagement to obtain limited assurance about whether any matters have come to our attention that cause us to believe that the company’s consolidated non-financial statement as marked with “Ω“ in the sustainability report, are not prepared, in all material respects, in accordance with Sections 315c in conjunction with 289c to 289e HGB and the EU Taxonomy Regulation and the Delegated Acts issued thereunder as well as the interpretation by management disclosed in section “EU Taxonomy” of the consolidated non-financial statement.

In a limited assurance engagement, the procedures performed are less extensive than in a reasonable assurance engagement, and accordingly, a substantially lower level of assurance is obtained. The selection of the assurance procedures is subject to the professional judgment of the assurance practitioner.

In the course of our assurance engagement we have, among other things, performed the following assurance procedures and other activities

• Inquiries of employees responsible for the materiality analysis at Group level to gain an understanding of the approach used to identify material topics and corresponding reporting boundaries of AIXTRON. A risk assessment, including a media analysis, of relevant information about AIXTRON’s sustainability performance in the reporting period.
• An evaluation of the design and implementation of systems and processes for the collection, processing and monitoring of disclosures on environmental, employee and social matters, human rights and anti-corruption and bribery, including the consolidation of data.
• Inquiries of personnel at Group level who are responsible for the determination of disclosures on concepts, due diligence processes, results and risks, the implementation of internal control procedures and the consolidation of disclosures.
• Inspection of selected internal and external documents. Analytical assessment of the data and trends of the quantitative disclosures reported for consolidation at Group level by all locations.
• Evaluation of local data collection, validation and reporting processes as well as the reliability of the reported data through a sample survey at selected sites.
• Interviews with responsible employees at Group level to gain an understanding of the process for identifying relevant economic activities according to the EU taxonomy.
• Evaluation of the design and implementation of systems and processes to assess taxonomy compliance (eligibility and alignment), particularly in the areas of Do Not Significantly Harm (DNSH) criteria and Minimum Social Safeguards (MSS).
• Evaluation of the design and implementation of systems and processes for the determination, processing and monitoring of disclosures on revenue, capital expenditures and operating expenses for the taxonomy-relevant economic activities.
• Assessment of the overall presentation of the disclosures.

In determining the disclosures in accordance with Article 8 of the EU Taxonomy Regulation, management is required to interpret undefined legal terms. Due to the immanent risk that undefined legal terms may be interpreted differently, the legal conformity of their interpretation and, accordingly, our assurance engagement thereon are subject to uncertainties.

Assurance Opinion

Based on the assurance procedures performed and the evidence obtained, nothing has come to our attention that causes us to believe that the consolidated non-financial statement of AIXTRON SE, Herzogenrath, for the period from January 1, 2023 to December 31, 2023, included in the sustainability report 2023 and marked with an "Ω", has not been prepared, in all material respects, in accordance with Sections 315c in conjunction with 289c to 289e HGB and the EU Taxonomy Regulation and the Delegated Acts issued thereunder as well as the interpretation by management as disclosed in section “EU Taxonomy” of the consolidated non-financial statement.

Restriction of Use

This assurance report is solely addressed to AIXTRON SE, Herzogenrath.

Our assignment for AIXTRON SE, Herzogenrath, and professional liability is governed by the General Engagement Terms for Wirtschaftsprüfer (German Public Auditors) and Wirtschaftsprüfungsgesellschaften (German Public Audit Firms) (Allgemeine Auftragsbedingungen für Wirtschaftsprüfer und Wirtschaftsprüfungsgesellschaften) in the version dated January 1, 2017 (https://www.kpmg.de/bescheinigungen/lib/ aab_english.pdf). By reading and using the information contained in this assurance report, each recipient confirms having taken note of provisions of the General Engagement Terms (including the limitation of our liability for negligence to EUR 4 million as stipulated in No. 9) and accepts the validity of the attached General Engagement Terms with respect to us.

Düsseldorf, February 26, 2024 KPMG AG

Wirtschaftsprüfungsgesellschaft

[Original German version signed by:]

Brandt                                                  Fielenbach

Wirtschaftsprüferin                         Wirtschaftsprüferin

Imprint

AIXTRON SE · Dornkaulstraße 2 · 52134 Herzogenrath · Germany · E-Mail: communications@aixtron.com

Reporting period: The reporting period is the calendar year 2023. It corresponds to the reporting period of the Annual Report. The previous report was published in February 2023.

Reporting cycle: The Sustainability Report is prepared and published annually with the company's Annual Report.

Accessibility: The text of this sustainability report is currently not barrier-free.

Auditor: KPMG AG Wirtschaftsprüfungsgesellschaft

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