公开(公告)号：JPH077075A

公开(公告)日：1995-01-10

申请号：JP4079194

申请日：1994-03-11

Applicant: IBM

Inventor： KURAUSU DEIITORITSUCHI BEIYAA ,  ANDORII SETEIAWAN YAPUSAA

IPC: H01L21/764 ,  H01L21/76 ,  H01L21/762 ,  H01L27/12

Abstract: PURPOSE: To provide a method for separating the lightly-doped silicon islands from each other and from a common substrate, and to provide its product. CONSTITUTION: A substrate 1 is covered by a first epitaxial layer which is heavily doped. The first layer is covered by a second epitaxial layer which is lightly doped. A pair of detached deep trenches 6 and 17, extending to the substrate 1 from the upper surface 7 of the second layer through the first layer, are formed. The inner walls of the trenches are covered by an oxide 8. A pair of reach-through diffusion regions heavily doped, which extend from the upper surface 7 of the first layer are positioned so as to perpendicular to the deep trenches 6 and 17, and they extend completely between the trenches. The first layer connected to the reach through diffusion regions heavily doped is removed by an anisotropic etching process, and the silicon islands are separated by air, except for a part which is brought into contact with the deep trenches 6 and 17 covered by oxide 8. Air isolation is favorably and partially substituted for the other dielectric material.