One approach to the fabrication of multiple silicon — insulator silicon layers that is compatible with existing silicon batch processing technology is to grow all of thelayers heteroepitaxially in a hydride reactor. We have grown multiple Si—Ins—Si layers using boron phosphide as the insulator. Up to 4 layers of BP—Si havebeen grown on silicon substrates and up to 2 layers have been grown on SOS substrates. MOS integrated circuits have been fabricated on the various Si layers. In general, the individual device quality and the performance of the ICs was lower as the number of layersincreased, however, even ICs fabricated on 4 layers of Si—BP—Si had characteristics comparable with SOS ICs. The growth process for production of the multiple heteroepitaxial films will be described. The characteristics of the ICs will be correlated with the film properties. Other possible candidates for insulators will be discussed.