Intermediate buffer films having a low plastic deformation threshold are provided for absorbing defects due to lattice mismatch and/or thermal coefficient of expansion mismatch between a substrate or layer support and an overlayer while concurrently providing a good template for subsequent crystalline growth at the overlayer. This is accomplished for diamond cubic structure substrates, such as Si or Ge or Si on sapphire or crystalline Si on glass, upon which are to be deposited lattice mismatch overlayers, such as, GaAs or ZnSe. Also, zinc blend type substrates, such as GaAs or InP may be employed with such intermediate buffer films. A characteristic of these intermediate buffer films is a substantially lower plastic deformation threshold compared to either the substrate support or the overlayer to be grown heteroepitaxially thereon. In particular, such high plastic deformable compound materials found suitable for such an intermediate buffer film are cubic III-V, II-VI or a I-VII zinc blend compound materials, respectively and specifically, (Zn.sub.X Cd.sub.Y Hg.sub.1-X-Y)(S.sub.A Se.sub.B Te.sub.1-A-B) and Cu(Cl.sub.X Br.sub.Y I.sub.1-X-Y) wherein X or Y respectively range between 0 and 1 such that X+ Y.ltoreq.1 and A and B respectively range between 0 and 1 such that A+B.ltoreq.1. Particular examples are GaAs, ZnSe, ZnS.sub.x Se.sub.1-x, CdS.sub.x Se.sub.1-x, HgS.sub.x Se.sub.1-x, CuCl, CuBr or CuI, et al.