Article for use under high vacuum at high temperature

摘要

Proposed is an article of pyrolytic boron nitride such as crucibles for use at a high temperature under an extremely high vacuum as in the molecular beam epitaxy. The article can be used in the high temperature, high vacuum process without the conventional elaborate and time-consuming degassing bake-out treatment because the article is wrapped in a wrapping film having a specified low moisture permeability immediately after a preliminary degassing treatment under specified conditions before the article is wrapped under a low-moisture atmosphere in a glove box.