A single crystal film of layered GaSe epitaxially grown onto a Si(1 1 1) substrate has been partly intercalated at room temperature under ultra-high vacuum. Then it was vacuum annealed sequentially at increasing temperatures up to 850 degreesC and studied at each step by low energy electron diffraction, Auger electron spectroscopy and photoemission yield spectroscopy. It is shown that the Fe-intercalated GaSe is perfectly stable until above 400 degreesC. At higher temperatures, the intercalated Fe is destabilised and is fully trapped into the Si substrate, restoring an Fe free GaSe crystalline film which decomposes above 600 degreesC.