The use of silicon dioxide as an isolation barrier to improve frequency and voltage ratings of integrated devices has been reported previously. The purpose of this paper is to introduce an improved dielectric film, which is far superior to silicon dioxide, and its application in fabricating integrated devices. With this improved isolation film, which may be formed in the epitaxial reactor, blocking voltage results exceed those obtained with silicon dioxide. This isolation film has extended device design freedoms. The formation and properties of this new isolating agent as well as several of its applications will be presented. Applications include integrated high frequency linear amplifiers with flat frequency response up to 150 Mc, complementary circuits and novel devices unachievable with conventional technology.