Abstract:
Semiconductor devices with high-K/metal gates are formed with spacers that are substantially resistant to subsequent etching to remove an overlying spacer, thereby avoiding replacement and increasing manufacturing throughput. Embodiments include forming a high-K/metal gate, having an upper surface and side surfaces, over a substrate, e.g., a SOI substrate, and sequentially forming, on the side surfaces of the high-K/metal gate, a first spacer of a non-oxide material, a second spacer, of a material different from that of the first spacer, and a third spacer, of a material different from that of the second spacer. After formation of source and drain regions, e.g., epitaxially grown silicon-germanium, the third spacer is etched with an etchant, such as hot phosphoric acid, to which the second spacer is substantially resistant, thereby avoiding replacement.
Abstract:
When forming high-k metal gate electrode structures in transistors of different conductivity type while also incorporating an embedded strain-inducing semiconductor alloy selectively in one type of transistor, superior process uniformity may be accomplished by selectively reducing the thickness of a dielectric cap material of a gate layer stack above the active region of transistors which do not receive the strain-inducing semiconductor alloy. In this case, superior confinement and thus integrity of sensitive gate materials may be accomplished in process strategies in which the sophisticated high-k metal gate electrode structures are formed in an early manufacturing stage, while, in a replacement gate approach, superior process uniformity is achieved upon exposing the surface of a placeholder electrode material.
Abstract:
When forming sophisticated semiconductor devices including transistors with sophisticated high-k metal gate electrode structures and a strain-inducing semiconductor alloy, transistor uniformity and performance may be enhanced by providing superior growth conditions during the selective epitaxial growth process. To this end, a semiconductor material may be preserved at the isolation regions in order to avoid the formation of pronounced shoulders. Furthermore, in some illustrative embodiments, additional mechanisms are implemented in order to avoid undue material loss, for instance upon removing a dielectric cap material and the like.
Abstract:
When forming sophisticated high-k metal gate electrode structures, the uniformity of the device characteristics may be enhanced by growing a threshold adjusting semiconductor alloy on the basis of a hard mask regime, which may result in a less pronounced surface topography, in particular in densely packed device areas. To this end, in some illustrative embodiments, a deposited hard mask material may be used for selectively providing an oxide mask of reduced thickness and superior uniformity.
Abstract:
Sophisticated gate electrode structures may be formed by providing a cap layer including a desired species that may diffuse into the gate dielectric material prior to performing a treatment for stabilizing the sensitive gate dielectric material. In this manner, complex high-k metal gate electrode structures may be formed on the basis of reduced temperatures and doses for a threshold adjusting species compared to conventional strategies. Moreover, a single metal-containing electrode material may be deposited for both types of transistors.
Abstract:
Improved semiconductor devices including metal gate electrodes are formed with reduced performance variability by reducing the initial high dopant concentration at the top portion of the silicon layer overlying the metal layer. Embodiments include reducing the dopant concentration in the upper portion of the silicon layer, by implanting a counter-dopant into the upper portion of the silicon layer, removing the high dopant concentration portion and replacing it with undoped or lightly doped silicon, and applying a gettering agent to the upper surface of the silicon layer to form a thin layer with the gettered dopant, which layer can be removed or retained.
Abstract:
A metal oxide semiconductor transistor device having a reduced gate height is provided. One embodiment of the device includes a substrate having a layer of semiconductor material, a gate structure overlying the layer of semiconductor material, and source/drain recesses formed in the semiconductor material adjacent to the gate structure, such that remaining semiconductor material is located below the source/drain recesses. The device also includes shallow source/drain implant regions formed in the remaining semiconductor material, and epitaxially grown, in situ doped, semiconductor material in the source/drain recesses.
Abstract:
A method of fabricating a semiconductor device with back side conductive plugs is provided here. The method begins by forming a gate structure overlying a semiconductor-on-insulator (SOI) substrate. The SOI substrate has a support layer, an insulating layer overlying the support layer, an active semiconductor region overlying the insulating layer, and an isolation region outboard of the active semiconductor region. A first section of the gate structure is formed overlying the isolation region and a second section of the gate structure is formed overlying the active semiconductor region. The method continues by forming source/drain regions in the active semiconductor region, and thereafter removing the support layer from the SOI substrate. Next, the method forms conductive plugs for the gate structure and the source/drain regions, where each of the conductive plugs passes through the insulating layer.
Abstract:
Methods for protecting gate stacks during fabrication of semiconductor devices and semiconductor devices fabricated from such methods are provided. Methods for fabricating a semiconductor device include providing a semiconductor substrate having an active region and a shallow trench isolation (STI) region. Epitaxial layer is formed on the active region to define a lateral overhang portion in a divot at the active region/STI region interface. A gate stack is formed having a first gate stack-forming layer overlying the semiconductor substrate. First gate stack-forming layer includes a non-conformal layer of metal gate-forming material which is directionally deposited to form a thinned break portion just below the lateral overhang portion. After the step of forming the gate stack, a first portion of the non-conformal layer is in the gate stack and a second portion is exposed. The thinned break portion at least partially isolates the first and second portions during subsequent etch chemistries.
Abstract:
Methods for protecting gate stacks during fabrication of semiconductor devices and semiconductor devices fabricated from such methods are provided. Methods for fabricating a semiconductor device include providing a semiconductor substrate having an active region and a shallow trench isolation (STI) region. Epitaxial layer is formed on the active region to define a lateral overhang portion in a divot at the active region/STI region interface. A gate stack is formed having a first gate stack-forming layer overlying the semiconductor substrate. First gate stack-forming layer includes a non-conformal layer of metal gate-forming material which is directionally deposited to form a thinned break portion just below the lateral overhang portion. After the step of forming the gate stack, a first portion of the non-conformal layer is in the gate stack and a second portion is exposed. The thinned break portion at least partially isolates the first and second portions during subsequent etch chemistries.