公开(公告)号：US11114491B2

公开(公告)日：2021-09-07

申请号：US16562396

申请日：2019-09-05

Applicant: KLA Corporation

Inventor： Yung-Ho Alex Chuang ,  Jehn-Huar Chern ,  John Fielden ,  Jingjing Zhang ,  David L. Brown ,  Sisir Yalamanchili

IPC: H01L27/146 ,  H01L27/148

Abstract: An image sensor utilizes a pure boron layer and a second epitaxial layer having a p-type dopant concentration gradient to enhance sensing DUV, VUV or EUV radiation. Sensing (circuit) elements and associated metal interconnects are fabricated on an upper surface of a first epitaxial layer, then the second epitaxial layer is formed on a lower surface of the first epitaxial layer, and then a pure boron layer is formed on the second epitaxial layer. The p-type dopant concentration gradient is generated by systematically increasing a concentration of p-type dopant in the gas used during deposition/growth of the second epitaxial layer such that a lowest p-type dopant concentration of the second epitaxial layer occurs immediately adjacent to the interface with the first epitaxial layer, and such that a highest p-type dopant concentration of the second epitaxial layer occurs immediately adjacent to the interface with pure boron layer.