Integrated circuit fabrication with boron etch-stop layer

Abstract

Aspects of the present disclosure include fabricating integrated circuit (IC) structures using a boron etch-stop layer, and IC structures with a boron-rich region therein. Methods of forming an IC structure according to the present disclosure can include: growing a conductive epitaxial layer on an upper surface of a semiconductor element; forming a boron etch-stop layer directly on an upper surface of the conductive epitaxial layer; forming an insulator on the boron etch-stop layer; forming an opening within the insulator to expose an upper surface of the boron etch-stop layer; annealing the boron etch-stop layer to drive boron into the conductive epitaxial layer, such that the boron etch-stop layer becomes a boron-rich region; and forming a contact to the boron-rich region within the opening, such that the contact is electrically connected to the semiconductor element through at least the conductive epitaxial layer.

Description

BACKGROUND[0001]The subject matter disclosed herein relates to the fabrication of field effect transistors (FETs). More specifically, embodiments of the present disclosure relate to methods of forming integrated circuit (IC) structures which use a boron layer used as an etch stop, and resulting IC structures which include a boron-rich region for transistors to electrically connect contacts to source and drain terminals.[0002]In integrated circuit (IC) structures, a transistor is a critical component for implementing digital circuitry designs. Generally, a transistor includes three electrical terminals: a source, a drain, and a gate. By applying different voltages to the gate terminal, the flow of electric current between the source and the drain can be turned on and off. The gate of a transistor can be formed as a gate stack structure (i.e., a “metal gate stack”) composed of a metal separated from a semiconductor element by a gate dielectric layer. Two processing paradigms for fabri...

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