公开(公告)号：EP0978872A1

公开(公告)日：2000-02-09

申请号：EP98830476.2

申请日：1998-08-03

Applicant: STMicroelectronics S.r.l.

Inventor： Mastromatteo, Ubaldo ,  Villa, Flavio ,  Barlocchi, Gabriele

IPC: H01L21/762

CPC classification number: H01L21/76294 ,  H01L21/76264 ,  H01L21/76272 ,  H01L21/76289

Abstract: The method comprises the following steps: selective anisotropic etching to form, in the substrate (2'), trenches (16) which extend to a predetermined depth from a major surface of the substrate (2') and between which portions (18) of the substrate (2') are defined, selective isotropic etching to enlarge the trenches (16), starting a predetermined distance from the major surface, thus reducing the thicknesses of the portions (18') of the substrate between adjacent trenches (16), selective oxidation to convert the portions (18') of reduced thickness of the substrate (2') into silicon dioxide (22) and to fill the trenches (16) with silicon dioxide, starting substantially from the said predetermined distance, and epitaxial growth of a silicon layer on the major surface of the substrate (2').
The method permits great freedom in the selection of the dimensional ratios between the trenches and the pillars and thus enables the necessary crystallographic quality of the epitaxial layer to be achieved, ensuring a continuous buried oxide layer.

Abstract translation: 该方法包括以下步骤：选择性各向异性蚀刻，以在衬底（2'）中形成从衬底（2'）的主表面延伸到预定深度并且在衬底（2'）的哪个部分（18）之间的沟槽（16） 衬底（2'）被限定为选择性各向同性蚀刻以扩大沟槽（16），从主表面开始预定距离，从而减小相邻沟槽（16）之间的衬底部分（18'）的厚度， 选择性氧化以基本上从所述预定距离开始将衬底（2'）的厚度减小的部分（18'）转换成二氧化硅（22）并用二氧化硅填充沟槽（16），并且外延生长 在衬底（2'）的主表面上的硅层。 该方法在选择沟槽和柱之间的尺寸比例方面允许很大的自由度，并且因此能够实现外延层的必要的晶体学质量，确保连续的掩埋氧化物层。