Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various layers using lithography to form circuit components and elements thereon.
A transistor is an element that is used frequently in semiconductor devices. There may be millions of transistors on a single integrated circuit (IC), for example. A common type of transistor used in semiconductor device fabrication is a metal oxide semiconductor field effect transistor (MOSFET), as an example. A transistor typically includes a gate dielectric disposed over a channel region in a substrate, and a gate electrode formed over the gate dielectric. A source region and a drain region are formed on either side of the channel region within the substrate.
Contacts are conductive features that are used to make electrical contact to regions of transistors, such as source regions, drain regions, and gate regions of semiconductor devices. Contacts are often connected between the active regions of the transistors and conductive lines that couple the transistor to other parts of the semiconductor device or to contact pads, for example.
As features of semiconductor devices are decreased in size, as is the trend in the semiconductor industry, forming conductive features such as contacts becomes more challenging.
Thus, what are needed in the art are improved methods of forming conductive features of semiconductor devices and structures thereof.