Fabrication of integrated circuit for radio frequency applications, involves producing opening in electrically insulating layer for partly covering outer portions along circumference of active region for bipolar transistor

摘要

An integrated circuit for radio frequency applications is fabricated by producing opening in an electrically insulating layer such that remaining portions of the insulating layer partly covers the active region for bipolar transistor, i.e. outer portions along a circumference of the active region. The insulating layer encapsulates and protects metal oxide semiconductor gate region. Fabrication of integrated circuit for radio frequency applications, comprises providing a silicon substrate. An active region (31) is formed for the bipolar transistor and an active region for the metal oxide semiconductor (MOS) device in the substrate. Field isolation areas (81) are formed around, in a horizontal plate, the active regions. A MOS gate region (111, 112) is formed on the active region for the MOS device. A layer (141) of an electrically insulating material is formed on the MOS gate region and on the active region for the bipolar transistor. A base region in the active region is defined for the bipolar transistor by means of producing an opening (143) in the electrically insulating layer. The opening in the insulating layer is produced such that the remaining portions of the insulating layer partly cover the active region for the bipolar transistor. The insulating layer remains on the MOS gate region to encapsulate and protect the MOS gate region during manufacturing steps, particularly including a step of oxidation, ion implantation and/or etching step.