Abstract
International scientific collaboration is central to technological progress, yet it is increasingly shaped by geopolitical tensions and rising techno-nationalist policies. Despite growing attention, systematic evidence on how such policies affect international research collaborations and scientific outcomes remains limited. This paper examines how rising U.S.–China tensions have reshaped international research collaboration in semiconductors, a strategically critical and highly globalized technology. Using bibliometric data linked to patent citations, we track collaboration patterns, publication output, research quality, and applied relevance of semiconductor science before and after the escalation of U.S. techno-nationalist policies in 2019. We compare U.S.–China collaborations with other international partnerships and exploit heterogeneity in firms’ pre-existing reliance on Chinese collaborators. We find that U.S.–China research collaborations decline sharply after 2019 and that U.S. firms more exposed to the loss of Chinese partners experience persistent reductions in high-impact and application-relevant research, despite stable publication volumes. At the same time, Chinese institutions expand both the quantity and quality of semiconductor research. These findings suggest that techno-nationalist policies may have unintended consequences for domestic innovation capacity.