Aixtron and Grand Chip Investment defy CFIUS objections to cancel the deal over U.S. national security concerns, and are appealing to U.S. President Barack Obama to approve the case in the next 15-days. The German Economic Ministry halted the acquisition business transaction, shortly after U.S. government representatives presented evidence suggesting Aixtron’s might pose a national security threat, which a Wall Street Journal reported mainly involves GaN epiwafer growing technology, a material that could be made to use improve military equipment such as radar.