Barrier materials for semiconductor devices

A barrier material deposited as a barrier film layer in a semiconductor device to reduce the interdiffusion of materials of varying electrical conductivity comprising adjacent layers in a semiconductor device is provided. The barrier material contains a transition metal, aluminum, silicon and nitrogen as essential ingredients. Suitable transition metals are tantalum and titanium. The material provides excellent resistance to diffusion across the range of temperatures occurring in an integrated circuit manufacturing process. The material also exhibits good adhesion to materials used in semiconductor processes.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates in general to the field of integrated circuit 
manufacturing technology and, more particularly, to a new material which 
can be deposited as a layer onto a semiconductor wafer to serve numerous 
purposes, including acting as an interdiffusion barrier or an adhesion 
promoter. 
2. Description of the Related Art 
In the manufacturing of integrated circuits, which are also referred to as 
semiconductor devices, numerous microelectronic circuits are 
simultaneously manufactured on semiconductor substrates. These substrates 
are referred to as wafers. A typical semiconductor wafer is comprised of a 
number of die. Each die contains at least one microelectronic circuit, 
which is typically replicated across all of a wafer's dies. One example of 
a microelectronic circuit which can be fabricated in this way is a dynamic 
random access memory or "DRAM". 
Although referred to as semiconductor devices, integrated circuits are in 
fact fabricated from and contain numerous materials of varying electrical 
properties. These include insulators or dielectrics, such as silicon 
dioxide, and conductors, such as aluminum or tungsten, in addition to 
semiconductors, such as silicon and germanium. The most common 
semiconductor employed is silicon. 
In state of the art integrated circuits, it is common for the design to 
require interfaces between layers of varying electrical properties. The 
interface between the two layers may constitute the entire surface of the 
die, or the interface may occur when conductive paths or openings are 
formed to connect or complete different circuits that have been fabricated 
within a die. One method to complete different circuits is through the use 
of conductive paths in or on an insulative layer which provide for an 
interface between a conductive, typically metal, layer and a 
semiconductive substrate, typically a silicon layer. Conductive paths of 
this variety are typically referred to as contact openings or contacts. 
The contact opening allows for an interface between the underlying 
semiconductive layer and the subsequently deposited conductive layer. 
It is common for a design to require an interface between other layers, 
such as between two different layers of metallic conductors, between an 
insulator and a metal conductor, between an oxide and a semiconductor, and 
between two different semiconductors. Interfaces between other layers are 
also known. Again, these interfaces may constitute the entire surface area 
of a die or they may be restricted to the narrow recesses of a conductive 
path formed between the two layers. Conductive paths providing an 
interface between pairs of layers may be referred to in the art as 
contacts or contact openings, or they may be referred to as vias or some 
other term. Because of the inconsistent use of these terms, the term 
conductive path will be used herein to refer to such openings formed in a 
semiconductor process to connect layers regardless of which layers are 
thereby connected. 
There are several difficulties inherent to these interfaces. One difficulty 
is due to the existence of common fabrication steps which require 
protracted annealing of the devices at elevated temperatures, often in 
excess of 500.degree. C. These temperatures are especially problematic for 
interfaces between semiconductor and conductor. At these temperatures the 
metallic conductor and the semiconductor can rapidly interdiffuse into the 
adjacent region. The interdiffusion of these materials is driven by the 
concentration gradients. This leads to a lower energy state of the 
composite material, which is the preferred stable state. This desire or 
trend toward a lower energy state is embodied in the Second Law of 
Thermodynamics which states, in effect, that whenever a spontaneous event 
takes place in the universe, it is accompanied by an overall increase in 
the degree of randomness (i.e., an increase in entropy). As a practical 
consequence of the Second Law of Thermodynamics, matter has a tendency to 
diffuse from areas of high concentration (i.e., high energy) to low 
concentration (i.e., low energy); hence, the interdiffusion of conductive 
and semiconductive layers. The interdiffusion changes the electrical 
properties of the two regions and in particular the semiconductor region, 
resulting in an increased likelihood of the production of inoperative 
devices. The interdiffusion of the two regions can also occur at room 
temperature, although at a much slower diffusion rate. Interdiffusion 
between other layers may also occur, increasing the likelihood of 
producing inoperable devices. 
These interdiffusion concerns generally have dictated the need for a 
barrier material to be deposited at the interface of the two layers when 
there is sufficient concern over interdiffusion of the two regions. 
Specifically the barrier material is deposited onto the surface of one 
layer prior to the deposition of another layer onto the barrier layer. For 
example, a barrier material can be deposited into a contact opening to 
prevent the interdiffusion between an underlying semiconductor layer and a 
subsequently deposited conductor layer. Titanium nitride (TiN) and 
titanium tungsten (TiW) are typical of the compounds used as barrier 
materials (i.e., to form a barrier layer). The barrier materials are 
typically deposited as a thin film or layer over the exposed surface of 
the die, including any intended interface. The deposited surfaces would 
include the walls and base of conductive paths. The thickness of these 
barrier films is typically in the range of 200 .ANG. to 1000 .ANG. 
although the use of films of other thicknesses is known. 
A second difficulty associated with these interfaces is a corollary to the 
first. Despite interdiffusion concerns, good contact between successive 
layers of the integrated circuit should be maintained. Therefore, any 
layer employed as a barrier layer to minimize interdiffusion should 
exhibit good adhesion qualities to the adjacent layers. Indeed, a thin 
film may be deposited strictly because of its adhesive properties when the 
two adjacent layers do not readily adhere to each other. Finally, barrier 
layers can also be used to tailor the electrical properties of contacts. 
One difficulty that limits the widespread use of certain materials as 
barrier and adhesive layers is their effectiveness at higher temperatures. 
Although generally effective at room temperature, certain materials may 
lose their barrier or adhesive properties at the high temperatures to 
which semiconductors are necessarily exposed. Barrier layers composed of 
TiN and TiW generally suffer from this limitation. Elevated temperatures 
are not only common for annealing steps but are often dictated by the 
limitations of the deposition techniques used to deposit materials onto 
the semiconductor wafer. Thus, a barrier material which does not exhibit a 
loss in either its barrier or adhesive properties at elevated temperatures 
would be extremely useful. 
A further complication in integrated circuit manufacturing is the ever 
increasing trend of reducing the size of the microelectronic circuits. As 
the size of these circuits, and therefore the size of die regions, 
decreases, the number of devices produced from any one wafer increases 
dramatically. However, as the size of these devices decreases, the 
percentage of reliable circuits produced on any one wafer becomes highly 
dependent on the ability to deposit films, including films deposited for 
barrier and adhesive purposes, uniformly across surfaces. These size 
reductions dictate that barrier materials be deposited at ever decreasing 
thicknesses, which means that these barriers are even more susceptible to 
elevated temperatures and the disastrous effects these temperatures can 
have on interdiffusion. Therefore, one requirement for any new barrier 
material, deposited as a barrier film or layer, would be that it exhibit 
greater inherent resistance to thermal energy than those materials 
previously employed. Additionally, it would be preferred that the adhesion 
properties of new barrier materials be at least as good as those 
previously employed. Finally, the trend in size reduction also dictates 
that new barrier materials must yield deposited films exhibiting greater 
uniformity in thickness (i.e. they must exhibit improved step coverage) 
than previous materials. The goal is to avoid the deposition of a barrier 
film which has holes or gaps within it. If present, these holes or gaps 
would tend to reduce the barrier properties of the film. As a corollary to 
this requirement, it would be preferable that any new material used as a 
barrier or adhesive layer could be deposited by those techniques currently 
used to deposit thin uniform films. Sputter deposition, chemical vapor 
deposition, and plasma enhanced chemical vapor deposition are the 
techniques most commonly employed to deposit the thin films of interest. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the invention, barrier layers can be 
deposited in a semiconductor process. The barrier layers prevent the 
interdiffusion of material comprising adjacent layers of a semiconductor 
device. In particular, the barrier layers act as diffusion barriers to 
prevent the interdiffusion of a conductor, typically a metal, and a 
semiconductor, typically silicon, across the broad range of temperatures 
that the semiconductor device is subjected to. The barrier layer comprises 
a composition containing varying amounts of a transition metal, aluminum, 
silicon, and nitrogen. Preferred transition metals include titanium and 
tantalum although other transition metals may be effectively employed. The 
barrier layer contains, by weight, from about 1% to about 95% transition 
metal, from about 1% to about 95% aluminum, from about 0.2% to about 95% 
silicon, and from about 1% to about 60% nitrogen. Preferably, the barrier 
layer contains from about 15% to about 80% transition metal, from about 5% 
to about 60% aluminum, from about 0.2% to about 20% silicon, and from 
about 20% to about 60% nitrogen. Even more preferably, the barrier layer 
contains from about 30% to about 40% transition metal, from about 10% to 
about 20% aluminum, from about 0.5% to about 10% silicon, and from about 
40% to about 50% nitrogen. 
The barrier layers of the present invention also act as adhesive layers 
between adjacent layers in a semiconductor device. The barrier layers are 
deposited upon the exposed horizontal surface of the device, but they are 
also deposited upon any other exposed surface, including both vertical 
walls and horizontal base of the narrow conductive paths that may be 
formed in a device. 
In accordance with another aspect of the invention, the barrier layers 
previously identified are further described as having been deposited onto 
a surface of a semiconductor device by methods which include reactive 
sputtering, chemical vapor deposition, and plasma enhanced chemical vapor 
deposition. 
In accordance with still another aspect of the invention, a semiconductor 
device is provided which comprises a semiconductor substrate layer and a 
barrier layer of the type previously identified. 
In accordance with yet another aspect of the invention, a semiconductor 
device is provided which comprises a conductive layer in addition to a 
semiconductive substrate layer and a barrier layer of the type previously 
identified. 
In accordance with a further aspect of the invention, there is provided a 
semiconductor device obtained by the steps of providing a semiconductive 
substrate layer and creating a barrier layer of the type previously 
identified. 
In accordance with an even further aspect of the invention, there is 
provided a semiconductor process which comprises the steps of providing a 
semiconductor substrate layer and creating a barrier layer of the type 
previously identified. Also provided is a semiconductor device obtained by 
the process. The barrier layer is deposited by methods known in the art 
including sputter deposition, chemical vapor deposition, and plasma 
enhanced chemical vapor deposition. Sputter deposition is particularly 
preferred. 
In accordance with a still further aspect of the present invention, there 
is provided a barrier layer of the type previously identified between two 
metal lines.

DESCRIPTION OF SPECIFIC EMBODIMENTS 
In the interest of clarity, not all features of an actual implementation 
into an integrated circuit process (i.e., semiconductor process) are 
described in this specification. This illustration is restricted to those 
aspects of a semiconductor process involving the deposition of thin films 
that can be deposited as layers, typically barrier or adhesive layers, in 
semiconductor processes. Conventional details of semiconductor processes, 
such as mask generation, resist casting, resist development, etching, 
doping, cleaning, implantation and annealing are not presented as such 
details are well known in the art of integrated circuit manufacture. 
Turning now to the drawings, a typical semiconductor wafer 10, as shown in 
FIG. 1, is comprised of a number of different regions, known as die 
regions 12. A semiconductor wafer 10 produced in accordance with one 
embodiment of the invention is depicted in FIG. 2. A wafer 10 includes an 
enhanced doped region 24, which may be obtained by an implantation process 
within a semiconductive substrate layer 26. The semiconductive substrate 
layer 26, generally comprising silicon, is coated with an insulative layer 
22, predominately boron-phosphorus-silicon glass (BPSG), which is etched 
to form conductive paths 20 through the insulative layer 22. By one of the 
methods described, a barrier layer 28 is deposited across the wafer such 
that it lines a conductive path 20. The barrier layer 28 is comprised of a 
composition containing a transition metal, aluminum, silicon, and 
nitrogen. Preferred transition metals are tantalum and titanium although 
other transition metals may be effectively employed. Preferably the 
composition comprising the barrier film layer 28 is deposited as an alloy 
of the transition metal, aluminum, silicon, and aluminum. This alloy may 
be referred to herein for convenience as MAlSiN, in which "M" refers to 
the transition metal, "Al" refers to aluminum, "Si" refers to silicon, and 
"N" refers to nitrogen. When a preferred transition metal, such as 
titanium (Ti) or tantalum (Ta), is expressly provided for, the symbol for 
this preferred transition metal will replace "M" in this shorthand 
description. This reference, MAlSiN, should not be construed as indicating 
any particular manner or form in which the elements are combined in the 
barrier layer 28. To the contrary, the shorthand reference is only 
intended to indicate which particular elements are contained within the 
barrier layer 28. 
In this specification the term "alloy" means a solid mixture. It does not 
necessarily indicate that the "alloy" or "mixture" is comprised primarily 
of metallic elements. The mixture is not necessarily completely 
homogeneous on a microscopic scale, and, in fact, it is expected that the 
relative concentration of each element will vary to some degree throughout 
the diffusion barrier. However, for each element, a concentration gradient 
with minimum and maximum extremes at the boundaries of the barrier layer 
28 does not exist, as there is admixture of all the elements throughout 
the barrier layer 28. 
The barrier layer 28 contains, by weight, from about 1% to about 95% 
transition metal, from about 1% to about 95% aluminum, from about 0.2% to 
about 95% silicon, and from about 1% to about 60% nitrogen. Preferably, 
the barrier layer 28 contains from about 15% to about 80% transition 
metal, from about 5% to about 60% aluminum, from about 0.2% to about 20% 
silicon, and from about 20% to about 60% nitrogen. Even more preferably, 
the barrier layer 28 contains from about 30% to about 40% transition 
metal, from about 10% to about 20% aluminum, from about 0.5% to about 10% 
silicon, and from about 40% to about 50% nitrogen. Preferably, the barrier 
film layer 28 is electrically semiconductive. 
The barrier layer 28 exhibits good adhesion to the conductive path 20 and 
the enhanced doped region 24 and, also, exhibits good step coverage. The 
barrier layer 28 deposited as described reduces interdiffusion of the 
silicon of the semiconductive substrate layer 26 and any metal 
subsequently deposited as part of a conductive layer 21. The barrier layer 
28 may be deposited onto the enhanced doped region 24 of the 
semiconductive substrate layer 26 as indicated in FIG. 2. However, the use 
of the barrier layer 28 of the present invention is not limited to this 
embodiment. Indeed, the barrier layer 28 may be deposited onto any exposed 
surface of the typically silicon-containing semiconductive substrate layer 
26 or any other suitable surface. Moreover, the term "silicon" as used 
here to describe the composition of the semiconductive substrate layer 26 
is also intended to encompass silicon-containing compounds, such as 
silicon dioxide and silicon nitride. 
The subsequent deposition of a conductive layer 21 is indicated in FIG. 3. 
Aluminum is typically used to form the conductive layer 21 although other 
conductive materials, such as tungsten or copper, may be used. The barrier 
layer 28 thus deposited also acts as an adhesive layer between the 
semiconductive substrate layer 26 and any subsequently deposited 
conductive layer 21. When the barrier layer 28 is deposited as indicated 
in FIG. 3, the result can be characterized in two ways. In the area of the 
semiconductor device encompassing the conductive path 20, a three layer 
structure consisting of a semiconductive substrate layer 26, a barrier 
layer 28, and a conductive layer 21 exists. In all other areas of the 
semiconductor device, a four layer structure exists with a insulative 
layer 22 located between the barrier layer 28 and the semiconductive 
substrate layer 26. 
Interfaces between conductive layers 21 and semiconductive layers, 
including semiconductive substrate layers 26, occur frequently in the 
designs for semiconductor devices. They may appear in the manner indicated 
in FIG. 3, or they may appear in other arrangements as well. In 
particular, interfaces between aluminum (conductor) and silicon 
(semiconductor) as depicted in FIG. 3 are common. When deposited as a 
barrier layer 28 between a conductive layer 21 and an enhanced doped 
region 24 of a semiconductive substrate layer 26, barrier materials 
comprising a composition of aluminum, silicon, nitrogen, and a transition 
metal preferably selected from titanium and tantalum reduce the 
interdiffusion of the conductive and semiconductive materials of the 
adjacent layers. In particular, unlike compositions of titanium and 
nitrogen in the form of TiN, titanium and tungsten in the form of TiW, and 
elemental Ti, these barrier layers 28 exhibit excellent barrier properties 
(i.e., thermal resistance) over a wide range of temperatures, including 
those in excess of 500.degree. C. often associated with annealing and 
deposition steps. These barrier layers 28 also exhibit excellent adhesion 
over a wide range of temperatures to layers in a semiconductor device, 
including in particular semiconductive substrate layers 26 and conductive 
layers 21. 
An additional advantage of these barrier layers 28 is afforded by the 
inclusion, within the composition, of those elements which typically 
comprise the adjacent layers in the semiconductor device, namely silicon 
and aluminum. This advantage is due to the fact that, because of the 
Second Law of Thermodynamics, material composing an enhanced doped region 
24 of a semiconductive substrate layer 26, for example silicon, will not 
only have a tendency to diffuse into an adjacent conductive layer 21, but 
will also have a tendency to diffuse into a barrier layer 28 deposited to 
prevent the initial diffusion concern. Diffusion of a conductive material 
from the conductive layer 21 into the barrier film layer 28 may also 
occur. Because of this, current barrier layers composed of materials like 
TiN can be expected to contain from 0.001% to 0.1% aluminum and silicon 
respectively when the adjacent semiconductive substrate layer 26 and 
conductive layer 21 consist essentially of these elements. By 
incorporating elements into the barrier layer 28 which are contained 
within the adjacent layers, diffusion is minimized. Diffusion of a 
particular element into the barrier layer 28 will only be significantly 
mitigated if the concentration of the particular element incorporated in 
the barrier film layer 28 exceeds that amount that can normally be 
expected to diffuse into the barrier layer 28. The concentrations of 
aluminum and silicon in the barrier film layer 28 should therefore be in 
excess of 0.2% when it is sought to minimize the diffusion of these 
elements. In these instances, further diffusion is significantly reduced 
because diffusion of a particular element, if it were to occur, would not 
result in an area of lower concentration. Therefore, the inclusion of 
silicon in the barrier film layer 28 will reduce the diffusion tendency of 
silicon contained in an adjacent semiconductive substrate layer 26, and 
the inclusion of aluminum will reduce the diffusion tendency of aluminum 
contained in an adjacent conductive layer 21. Likewise, the inclusion of a 
transition metal, such as tantalum or titanium, will reduce the diffusion 
tendency of these elements if they are contained within an adjacent 
conductive layer 21. It should be noted, however, that it is not a 
requirement that tantalum be employed only when adjacent layers contain 
tantalum, that aluminum be employed only when adjacent layers contain 
aluminum, or that titanium be employed only when adjacent layers contain 
titanium. Likewise, diffusion into a barrier layer of elements comprising 
other layers (i.e., layers other than a semiconductive substrate layer 26 
and conductive layer 21) in a semiconductor device can be minimized by 
incorporating those elements into a barrier layer placed between the two 
layers. 
The barrier layer 28 differs in another way from those previously known 
barrier layers 28 consisting essentially of a transition metal nitride 
that contained aluminum and silicon as a result of diffusion from adjacent 
layers. These previously known barrier layers 28 are characterized by a 
concentration gradient for the aluminum and silicon contained therein. The 
concentration of either one of these elements is at its highest near the 
interface with the adjacent layer containing the particular element. 
Concentration decreases significantly as one moves away from this 
interface. The result is a barrier layer 28 having a high concentration of 
aluminum and hardly any silicon in that portion of the film adjacent to 
the conductive layer 21 and a high concentration of silicon and hardly any 
aluminum in that portion of the film adjacent to the semiconductive 
substrate layer 26. The term "high" in the previous sentence is relative, 
as the total concentration of aluminum or silicon is not expected to 
exceed 0.1% in these previously known barrier layers 28. In contrast, the 
barrier layers 28 are characterized by a more homogeneous distribution of 
the deposited elements. Individual atoms of the chosen transition metal, 
aluminum, silicon, and nitrogen can be expected to be located throughout 
the barrier layer 28. 
These barrier materials can be deposited onto the surface of a 
semiconductor by any of the known techniques. However, to deposit these 
barrier materials in a conductive path 20 to form a barrier layer 28 
between a conductive layer 21 and a semiconductive substrate layer 26, the 
deposition method employed should be capable of depositing thin films, 
generally less than 3000 .ANG., which exhibit high purity and density and 
relatively uniform step coverage. The thickness of the barrier layer 28 is 
preferably about 50 .ANG. to 2000 .ANG.. Reactive sputtering, chemical 
vapor deposition, and plasma enhanced chemical vapor deposition techniques 
generally known in the art can be used. 
Fabrication of a semiconductor device incorporating a barrier layer 28 of 
one embodiment of the present invention comprises the steps of providing a 
semiconductive surface and creating a barrier layer containing a 
transition metal, aluminum, silicon, and nitrogen. The fabrication further 
comprises the step of creating a conductive layer on the barrier layer. 
This step comprises creating a layer of aluminum or copper. The step of 
providing a semiconductive substrate comprises providing a semiconductor 
wafer having a semiconductive substrate layer 26. This semiconductive 
substrate layer 26 is comprised of silicon, and preferably the silicon is 
doped. Alternatively, this semiconductive substrate layer is comprised of 
silicon dioxide or another silicon containing compound. The transition 
metal is selected from titanium and tantalum. Preferably, the step of 
creating the barrier layer is accomplished by reactive sputtering. 
When reactive sputtering is employed, a target containing the transition 
metal, aluminum, and silicon is preferably used as the source of these 
elements. The target and the wafer upon which the elements are to be 
deposited upon are contained within a sputtering chamber. The target is 
bombarded with positive inert ions with kinetic energy far exceeding the 
heat of sublimation of the target elements. This bombardment results in 
the dislodging of target atoms and their ejection into the gas phase 
succeeded by their deposition onto the substrate or other depositing 
surface. In this instance, the gas space in the chamber contains nitrogen 
and may additionally contain argon. A typical and acceptable 
argon/nitrogen ratio is 70%/30%. 
As known in the art, the composition of the deposited barrier layer 28 can 
be controlled by altering the composition of the target and the kinetic 
energy of the ions used to bombard the target. Sputter conditions 
typically employed in the field are acceptable for the deposition of the 
barrier layers 28 of this invention. Preferable conditions include power 
levels between about 5 kW and about 20 kW, temperatures between about 
150.degree. C. and about 300.degree. C., and pressures between about 1 
millitorr and about 10 millitorr. A temperature about 200.degree. C. is 
particularly preferred. 
When chemical vapor deposition or plasma enhanced chemical vapor deposition 
methods known in the art are employed, individual sources of the desired 
transition metal, aluminum, and silicon as known in the art can be 
employed. For the transition metal and aluminum, these sources may be 
organometallic. For the transition metal, acceptable organometallic 
precursors include those of the general formula M(NR.sub.2).sub.x, where M 
is the desired transition metal, R is either hydrogen (H) or a carbon 
containing radical, and x is equal to the oxidation state of the 
transition metal M. The preferred transition metals are titanium and 
tantalum. For titanium, x will typically be 4. For tantalum, x will 
typically be 5. Known and acceptable organometallic sources for titanium 
include Ti(N(CH.sub.3).sub.2).sub.4 and Ti(N(C.sub.2 H.sub.5)).sub.4. 
Similarly known organometallic sources of tantalum and aluminum, such as 
dimethylethylamine (DMEAA) or dimethyl-aluminumhydride (DMAH), are 
acceptable. For silicon, typical and acceptable sources are hydrides such 
as SiH.sub.4. Nitrogen is generally provided by a gaseous source, such as 
N.sub.2, NH.sub.3, or hydrazine containing sources. 
Regardless of the deposition method employed, the deposited barrier layer 
28 should comprise by weight from about 1% to about 95% transition metal, 
from about 1% to about 95% aluminum, from about 0.2% to about 95% silicon, 
and from about 1% to about 60% nitrogen. 
Preferably, the barrier layer 28 contains from about 15% to about 80% 
transition metal, from about 5% to about 60% aluminum, from about 0.2% to 
about 20% silicon, and from about 20% to about 60% nitrogen. Even more 
preferably, the barrier layer 28 contains from about 30% to about 40% 
transition metal, from about 10% to about 20% aluminum, from about 0.5% to 
about 10% silicon, and from about 40% to about 50% nitrogen. 
In other embodiments, the described material can be deposited between other 
layers in a semiconductor device. These would include, but are not limited 
to, between two different layers of metallic conductors; between an 
insulator and a metal conductor; between an oxide and a semiconductor; and 
between two different semiconductors. The barrier materials could 
therefore be employed not only to deposit thin films of a composition 
containing a transition metal, aluminum, silicon, and nitrogen along the 
surfaces of any conductive path 20, but also to deposit these same films 
along any surface in a semiconductor device. 
In another embodiment, a semiconductor device is provided that includes a 
semiconductive substrate layer 26 and a barrier layer 28 comprising a 
composition composed of varying amounts of a transition metal, aluminum, 
silicon, and nitrogen deposited onto the semiconductive substrate layer 
26, wherein preferred transition metals include tantalum and titanium. 
Preferably, the device further comprises a conductive layer 21 deposited 
onto the barrier layer 28, wherein the conductive layer 21 generally 
comprises a metal such as aluminum. Without regard to the layers between 
which the composition is deposited, the thickness of this material, used 
as a barrier layer 28, is typically between 50 .ANG. and 2000 .ANG. thick 
although films of other thicknesses are known. The composition, deposited 
as a barrier layer 28, is comprised by weight from about 1% to about 95% 
transition metal, from about 1% to about 95% aluminum, from about 0.2% to 
about 95% silicon, and from about 1% to about 60% nitrogen. Preferably, 
the barrier layer 28 contains from about 15% to about 80% transition 
metal, from about 5% to about 60% aluminum, from about 0.2% to about 20% 
silicon, and from about 20% to about 60% nitrogen. Even more preferably, 
the barrier layer 28 contains from about 30% to about 40% transition 
metal, from about 10% to about 20% aluminum, from about 0.5% to about 10% 
silicon, and from about 40% to about 50% nitrogen. 
Although the primary use of the described composition is as a layer 
deposited in a conductive path 20 as a barrier layer 28 between an 
underlying semiconductive substrate layer 26 and a subsequently deposited 
conductive layer 21, the composition can be used between other layers of a 
semiconductor device to provide barrier or adhesive properties. The 
composition can be deposited at any surface defining an interface between 
layers of interest, including the vertical walls and horizontal base of 
conductive paths. 
In yet another aspect, there is provided a semiconductor process which 
comprises the stops of providing a semiconductive substrate layer 26 and 
creating a barrier layer 28 comprising by weight from about 1% to about 
60% nitrogen. Preferably, the barrier layer 28 contains from about 15% to 
about 80% transition metal, from about 5% to about 60% aluminum, from 
about 0.2% to about 20% silicon, and from about 20% to about 60% nitrogen. 
Even more preferably, the barrier layer 28 contains from about 30% to 
about 40% transition metal, from about 10% to about 20% aluminum, from 
about 0.5% to about 10% silicon, and from about 40% to about 50% nitrogen. 
The barrier layer can be deposited by a technique chosen from reactive 
sputtering, chemical vapor deposition, and plasma enhanced chemical vapor 
deposition. In yet another aspect, there is provided semiconductor devices 
obtained by this process. 
While the invention is susceptible to various modifications and alternative 
forms, specific embodiments have been shown by way of example in drawings 
and have been described in detail herein. However, it should be understood 
that the invention is not intended to be limited to the particular forms 
disclosed. Rather, the invention is to cover all modifications, 
equivalents, and alternatives falling within the spirit and scope of the 
invention as defined by the appended claims.