Self-aligned contact for silicon-on-insulator devices

Abstract

A method for forming a self-aligned contact to an ultra-thin body transistor first providing an ultra-thin body transistor with source and drain regions operated by a gate stack; forming a contact spacer on the gate stack; forming a passivation layer overlying the transistor; forming a contact hole in the passivation layer exposing the contact spacer and the source / drain regions; filling the contact hole with an electrically conductive material; and establishing electrical communication with the source / drain region.

Description

FIELD OF THE INVENTION [0001] The present invention generally relates to the field of semiconductor devices and more particularly, to the manufacture of advanced metal oxide semiconductor field effect transistors (MOSFETs) with self-aligned contacts. BACKGROUND OF THE INVENTION [0002] Transistor scaling has provided continued improvement in speed performance and circuit density in ultra-large scale integrated (ULSI) chips over the past few decades. As the gate length of the conventional bulk metal-oxide-semiconductor field-effect transistor (MOSFET) is reduced, it suffers from problems related to the inability of the gate to substantially control the on and off states of the channel. Phenomena such as reduced gate control associated with transistors with short channel lengths are termed short-channel effects. Increased body doping concentration, reduced gate oxide thickness, and ultra-shallow source / drain junctions are ways to suppress short-channel effects. However, for device scal...

AI Technical Summary

Benefits of technology

[0019] In the self-aligned contact device, the multiple-gate transistor may be a double-gate transistor, a triple-gate transistor, or an omega field-effect transistor. The gate stack may be a gate electrode, which may be formed of poly-crystalline silicon or poly-crystalline silicon-germanium. The gate electrode may be formed of a refractory metal. The gate stack may include a gate electrode and a gate capping layer which may be formed of a dielectric, of a silicon nitride, or of a silicon nitride layer overlying a

Problems solved by technology

As the gate length of the conventional bulk metal-oxide-semiconductor field-effect transistor (MOSFET) is reduced, it suffers from problems related to the inability of the gate to substantially control the on and off states of the channel.

However, for device scaling well into the sub-30 nm regime, the requirements for body doping concentration, gate oxide thickness, and source / drain (S / D) doping profiles become increasingly difficult to meet in conventional device structures where bulk silicon substrates are employed.

In addition, variations in the series resistance in the source and drain regions of the device result in significant variations in the electrical characteristics of the device.

Images