Abstract: The present invention is directed to a method of forming an FeRAM integrated circuit, which includes performing a capacitor stack etch to define the FeRAM capacitor. The method comprises etching a PZT ferroelectric layer with a high temperature BCl3 etch which provides substantial selectivity with respect to the hard mask. Alternatively, the PZT ferroelectric layer is etch using a low temperature fluorine component etch chemistry such as CHF3 to provide a non-vertical PZT sidewall profile. Such a profile prevents conductive material associated with a subsequent bottom electrode layer etch from depositing on the PZT sidewall, thereby preventing leakage or a “shorting out” of the resulting FeRAM capacitor.

Abstract: Semiconductor devices and fabrication methods are disclosed, in which one or more low silicon-hydrogen SiN barriers are provided to inhibit hydrogen diffusion into ferroelectric capacitors and into transistor gate dielectric interface areas. The barriers may be used as etch stop layers in various levels of the semiconductor device structure above and/or below the level at which the ferroelectric capacitors are formed so as to reduce the hydrogen related degradation of the switched polarization properties of the ferroelectric capacitors and to reduce negative bias temperature instability in the device transistors.

Abstract: Semiconductor devices and fabrication methods are presented, in which a hydrogen barrier is provided above a ferroelectric capacitor to prevent degradation of the ferroelectric material during back-end manufacturing processes employing hydrogen. The hydrogen barrier comprises silicon rich silicon oxide or amorphous silicon, which can be used in combination with an aluminum oxide layer to inhibit diffusion of process-related hydrogen into the ferroelectric capacitor layer.

Abstract: Hydrogen barriers and fabrication methods are provided for protecting ferroelectric capacitors (CFE) from hydrogen diffusion in semiconductor devices (102), wherein nitrided aluminum oxide (N—AlOx) is formed over a ferroelectric capacitor (CFE), and one or more silicon nitride layers (112, 117) are formed over the nitrided aluminum oxide (N—AlOx). Hydrogen barriers are also provided in which an aluminum oxide (AlOx, N—AlOx) is formed over the ferroelectric capacitors (CFE), with two or more silicon nitride layers (112, 117) formed over the aluminum oxide (AlOx, N—AlOx), wherein the second silicon nitride layer (112) comprises a low silicon-hydrogen SiN material.

Abstract: A via etch to contact a capacitor with ferroelectric between electrodes together with dielectric on an insulating diffusion barrier includes two-step etch with F-based dielectric etch and Cl- and F-based barrier etch.

Abstract: The present invention forms sidewall diffusion barrier layer(s) that mitigate hydrogen contamination of ferroelectric capacitors. Sidewall diffusion barrier layer(s) of the present invention are formed via a physical vapor deposition process at a low temperature. By so doing, the sidewall diffusion barrier layer(s) are substantially amorphous and provide superior protection against hydrogen diffusion than conventional and/or crystalline sidewall diffusion barrier layers.

Abstract: The present invention is directed to a method of forming a ferroelectric capacitor having a (111) PZT texture. The method includes forming a smooth bottom electrode diffusion barrier layer that facilitates a preferential (111) texture in the subsequently formed bottom electrode layer. The (111) bottom electrode layer texture than facilitates a high quality (111) texture in the overlying PZT layer, thereby improving bit-to-bit polarization charge uniformity for various capacitors as the ferroelectric capacitor sizes continue to shrink.

Abstract: A field effect semiconductor device comprising a high permittivity silicate gate dielectric and a method of forming the same are disclosed herein. The device comprises a silicon substrate 20 having a semiconducting channel region 24 formed therein. A metal silicate gate dielectric layer 36 is formed over this substrate, followed by a conductive gate 38. Silicate layer 36 may be, e.g., hafnium silicate, such that the dielectric constant of the gate dielectric is significantly higher than the dielectric constant of silicon dioxide. However, the silicate gate dielectric may also be designed to have the advantages of silicon dioxide, e.g. high breakdown, low interface state density, and high stability. The present invention includes methods for depositing both amorphous and polycrystalline silicate layers, as well as graded composition silicate layers.

Abstract: A ferroelectric memory device comprises a logic programmable capacitance reference circuit. The circuit is adapted to generate a reference voltage during a sense mode of operation, wherein the reference voltage comprises a value that is a function of one more memory conditions. The memory device further comprises a bit line pair, wherein a first bit line of the bit line pair has a ferroelectric capacitor coupled thereof for sensing thereof, and a second bit line of the bit line pair is coupled to the reference voltage. A sense circuit is coupled to the bit line pair and is configured to detect a data state associated with the ferroelectric capacitor using a voltage associated with the first bit line and reference voltage on the second bit line.

Abstract: The present invention is directed to a method of forming an FeRAM integrated circuit, which includes forming a multi-layer hard mask. The multi-layer hard mask comprises a hard masking layer overlying an etch stop layer. The etch stop layer is substantially more selective than the overlying masking layer with respect to an etch employed to remove the bottom electrode diffusion barrier layer. Therefore during an etch of the capacitor stack, an etch of the bottom electrode diffusion barrier layer results in a substantially complete removal of the hard masking layer. However, due to the substantial selectivity (e.g., 10:1 or more) of the etch stop layer with respect to the overlying masking layer, the etch stop layer completely protects the underlying top electrode, thereby preventing exposure thereof.

Abstract: An embodiment of the invention is a method of cleaning a material stack 2that has a hard mask top layer 8. The method involves cleaning the material stack 2with a fluorine-based plasma etch. The method further involves rinsing the material stack 2with a wet clean process.

Abstract: A ferroelectric memory device is disclosed and comprises a logic programmable capacitance reference circuit. The circuit is adapted to generate a reference voltage during a sense mode of operation, wherein the reference voltage comprises a value that is a function of one or more memory conditions. The memory device further comprises a bit line pair, wherein a first bit line of the bit line pair has a ferroelectric capacitor coupled thereto for sensing thereof, and a second bit line of the bit line pair is coupled to the reference voltage. A sense circuit is coupled to the bit line pair and is configured to detect a data state associated with the ferroelectric capacitor using a voltage associated with the first bit line and the reference voltage on the second bit line.

Abstract: An embodiment of the invention is a method of eliminating the surface roughness of the hardmask 4 of a ferroelectric capacitor stacks 2 using a BCl3-based plasma etch.

Abstract: A ferroelectric memory capacitor is formed by forming a barrier layer, a first metal layer, a ferroelectric layer, a second metal layer, and a hard mask layer, on dielectric layer (70). Using the patterned hard mask layer (255), the layers are etched to form an etched barrier layer (205), and etched first metal layer (215), and etched ferroelectric layer (225), and etched second metal layers (235, 245). The etched layers form a ferroelectric memory capacitor (270) with sidewalls that form an angle with the plane of the upper surface of the dielectric layer (70) between 78° and 88°. The processes used to etch the layers are plasma processes performed at temperatures between 200° C. and 500° C.

Abstract: The present invention is directed to a method of forming an FeRAM integrated circuit, which includes forming a TiAlON bottom electrode diffusion barrier layer prior to formation of the bottom electrode layer in an FeRAM capacitor stack. Subsequently, when performing the capacitor stack etch, the portion of the TiAlON diffusion barrier layer not covered by the FeRAM capacitor stack is etched substantially anisotropically due to the oxygen within the TiAlON diffusion barrier layer substantially preventing a lateral etching thereof. In the above manner, an undercut of the TiAlON diffusion barrier layer under the FeRAM capacitor stack is prevented. In another aspect of the invention, a method of forming an FeRAM capacitor comprises forming a multi-layer bottom electrode diffusion barrier layer. Such formation comprises forming a TiN layer over the interlayer dielectric layer and the conductive contact and forming a diffusion barrier layer thereover.

Abstract: The present invention is directed to a method of forming an FeRAM integrated circuit, which includes evaluating the capacitor stack to determine the efficacy of the sidewall diffusion barrier layer deposition. When evaluating the capacitor stack after etching a masking layer portion of the hard mask, if “ears” are seen on top of the stack, the sidewall diffusion barrier layer is sufficiently thick to provide an adequate sidewall barrier. Evaluation may be performed using a standard or tilt scanning electron microscope, for example.

Abstract: The present invention forms sidewall diffusion barrier layer(s) that mitigate hydrogen contamination of ferroelectric capacitors. Sidewall diffusion barrier layer(s) of the present invention are formed via a physical vapor deposition process at a low temperature. By so doing, the sidewall diffusion barrier layer(s) are substantially amorphous and provide superior protection against hydrogen diffusion than conventional and/or crystalline sidewall diffusion barrier layers.

Abstract: A versatile system for forming diffusion barriers in semiconductor processing that simplifies device processing, utilizing existing production compounds and materials while resulting in uniform and proper device structuring, is disclosed, providing a system using a reactive plasma to selectively form diffusion barriers and provide selective oxidation.

Abstract: One aspect of the invention relates to a method of manufacturing FeRAM, and in particular, plasma etching a bottom electrode layer in a ferroelectric capacitor stack. According to the method, plasma etching is carried out at a relatively low bias in an atmosphere that includes a halogen compound and an oxygen source containing carbon, such as carbon monoxide or carbon dioxide. The invention prevents shorting along the sidewalls of the capacitor stack, which can otherwise be caused by re-deposition of material released from the bottom electrode layer. The gas composition and temperature are such that chemical reaction substantially contributes to the etch rate as compared to purely physical etching. In one embodiment, the capacitor stack is etched with a hard mask that include TiAlN and the atmosphere is oxidizing to an extent that increases the selectivity between the hard mask and the bottom electrode layer.

Abstract: The present invention is directed to a method of forming an FeRAM integrated circuit, which includes forming a sidewall diffusion barrier prior to etching the bottom electrode diffusion barrier layer. The sidewall diffusion barrier layer is then etched prior to the bottom electrode diffusion barrier layer. In patterning an AlOx sidewall diffusion barrier layer prior to etching the underlying bottom electrode diffusion barrier layer, the etch chemistry comprises BCl3+Ar. The BCl3 is effective in etching the AlOx with a good selectivity to the underlying nitride hard mask on top of the capacitor stack (e.g., TiAlN) and nitride bottom electrode diffusion barrier (e.g., TiAlON with small oxygen content) between the neighboring capacitor stacks. The Ar may be added to the etch chemistry because the resulting surface (of a top portion of the hard mask and the bottom electrode diffusion barrier) is smoother.