WO2000038213A2

WO2000038213A2 - Physical vapor deposition of semiconducting and insulating materials

Info

Publication number: WO2000038213A2
Application number: PCT/US1999/030476
Authority: WO
Inventors: Visweswaren Sivaramakrishnan; Vicente Lim; Kaushal K. Singh
Original assignee: Applied Materials, Inc.
Priority date: 1998-12-21
Filing date: 1999-12-20
Publication date: 2000-06-29
Also published as: EP1141997A2; JP2002533574A; TW454245B; WO2000038213A3; KR20010089674A

Abstract

The invention provides an apparatus for depositing semiconducting, insulating, and particularly, high dielectric constant (HDC) material, such as barium strontium titanate, on a substrate through reactive sputtering. The apparatus comprises a physical vapor deposition chamber having an asymmetric bipolar pulsed direct current power source supplying a first bias to a target and a second bias to the substrate support member in the chamber. The pulsed direct current power source supplies an electrical waveform comprising a negative deposition voltage that attracts the argon ions to cause sputtering from the target and a reverse small positive neutralization voltage to cause charge neutralisation of the target that eliminates arcing and micro-arcing on the target surface. Preferably, the first bias is synchronized with the second bias for the deposition period and the neutralization period. A floating-ground shield surrounds the processing region between the target and the substrate. A first gast inlet introduces a gas for the plasma through the top portion of the chamber, and a second gas inlet introduces a reaction gas adjacent the substrate surface to react with the sputtered material to form the HDC film on the substrate.

Description

PHYSICAL VAPOR DEPOSITION OF SEMICONDUCTING AND INSULATING MATERIALS

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention generally relates to a physical vapor deposition system. More particularly, the invention relates to a physical vapor deposition system for depositing conducting, semiconducting and/or insulating materials onto a substrate.

Background of the Related Art

Physical vapor deposition (PVD) systems are well known in the field of semiconductor processing for forming metal films. Generally, a power supply connected to a processing chamber creates an electrical potential between a cathode and an anode within the chamber and generates a plasma of a processing gas in the region between the cathode and the anode. The ions from the plasma bombard a target (cathode-biased) and sputter material from the target which then deposits onto a substrate (anode-biased). However, to form insulating films having high dielectric constants (defined herein as having a dielectric constant k greater than about 50) using PVD, a reactive sputtering process is required in which the sputtered material from the target reacts with ions in the plasma to form a high k material which deposits onto the substrate. Reactive sputtering is typically used to form high dielectric constant (HDC) films such as barium strontium titanate (BST) on substrates. However a number of problems are encountered using the reactive sputtering process. Figure 1 is a cross sectional view of a typical PVD chamber useful for depositing a

HDP film such as a BST film. The PVD chamber 10 generally includes a chamber enclosure 12, a substrate support member 14, a target 16, a shield 18, a clamp ring 20, a gas inlet 22, a gas exhaust 24, a magnet assembly 26 and a combined RF/DC power source 28. During processing, a substrate 30 is placed on the substrate support member 14 and a processing gas is introduced through the gas inlet 22 disposed between the edge of the target and the top portion of the shield into a processing region 32 defined by the target 16, the substrate 30 and the shield 18. For deposition of a BST film, the processing gas typically comprises argon and oxygen, wherein argon serves as the gas source for the plasma ions that bombard the target 16 and oxygen reacts with the sputtered atoms from the target 16 to oxidize the metal atoms and form a BST film which is deposited onto the substrate 30. The RF/DC power source 28 supplies a combined RF/DC power to the chamber to strike and maintain a plasma of the processing gas in the processing region 32. Typically, the RF/DC power source 28 is electrically connected to the target 16 while the substrate support member 14 and the shield 18 are grounded during processing. During deposition, the ions in the plasma bombard the target to sputter material from the target surface. The sputtered material reacts with ions in the plasma and forms the desired film on the surface of the substrate. The above described PVD chamber is useable for reactive sputtering of HDC materials. However, a number of problems are encountered in using typical PVD to deposit HDC materials.

First, PVD of highly insulating films or high dielectric constant films by reactive sputtering of a conductive target using a direct current process power results in a build-up of positive electrical charges on the target. As the positive electrical charges reach an excess level, arcing occurs between the target surface and the grounded chamber walls or the grounded shield disposed between the target and the chamber walls. As a result of arcing, contaminant particles (both large and small particles) are generated and cause damage to the substrate, resulting in a defective substrate which must be discarded.

Second, the reaction between the ions in the plasma and the target material can occur on the target sputtering surface and form spots of HDC film on the target sputtering surface because the reactive gas is introduced into the processing region through gas inlets disposed adjacent to the target sputtering surface. The HDC film formed on the target sputtering surface exacerbates the arcing problem by allowing more positive charges to form on the target surface. The HDC film formed on the target sputtering surface also decreases the sputterable target surface, resulting in a reduced sputtering rate and a degraded sputtering uniformity across the sputtering surface.

Third, when RF power is applied to the target, changes in micro-resistivity on the target sputtering surface causes micro-arcing on the target surface. This micro-arcing phenomenon along with the arcing problem may cause serious damage to the target and result in large pieces of the target material being released into the chamber. In addition to the damage to the target, the pieces dislodged from the target may damage other components within the chamber, resulting in downtime associated with cleaning the chamber, replacing the target and other damaged components, and restoring the chamber to processing conditions. The micro-arcing phenomenon also causes contaminant generation, resulting in defects on the substrate as described above.

Another problem encountered in PVD of BST is that the resulting film properties are non-uniform and inconsistent within one substrate as well as between different substrates. Generally, the non-uniformity and inconsistency problem results from a current magnet source/target configuration that does not provide uniform erosion of the target material from the target sputtering surface. The non-uniform erosion of the target material leads to uncontrolled composition of the sputtered material. The resulting film capacitance non- uniformity can exceed fifteen percent (15%) deviation, and the thickness of the deposited film can vary up to eight percent (8%) within one substrate and from substrate to substrate. Typically, more than ten thousand (10,000) particle defects (contaminant particles having sizes < 0.3mm) may form on the substrate, and the resulting film has poor grain orientation and crystal quality. Because the target material is typically a composition of different metals, a uniform erosion of the target material is required to ensure a proper proportion of each of the metals for the desired reaction to occur to form the deposited film on the substrate.

Another problem associated with physical damage to the target is that the typical target does not possess the mechanical strength to prevent target breakage due to pressure exerted on the target during processing. For example, the typical target, when exposed to a pressure of 3 kgf/cπr, exhibits a backing plate deflection of 1.100 mm. The backing plate deflection is a measure of the flex or bend of the backing plate under a certain pressure. Because the typical target has a high deflection, pieces of the sputterable material may break off from the target and cause substrate defects.

Furthermore, the currently practiced PVD of BST has not demonstrated to ability to provide conformal step coverage of high aspect ratio features, such as a sub-micron aperture having an aspect ratio greater than 1:1. Also, the target lifetime and the process kit lifetime are both severely reduced (to less than 50 KWH) because of the excess particle contamination. The throughput of the deposition system is also reduced because the chamber requires frequent cleaning. Therefore, there exists a need for a deposition system that eliminates arcing and micro arcing on the target and forms high quality, high k dielectric films, particularly BST films. It would be desirable for the deposition system to provide high deposition rates and high throughput as well as uniform and consistent processing results. There is also a need for a deposition system for depositing high k dielectric material into high aspect ratio features.

SUMMARY OF THE INVENTION The invention generally provides an apparatus for depositing semiconducting and insulating mateπals onto a substrate More specifically, the invention provides an apparatus for depositing a high dielectric constant (HDC) mateπal, such as barium strontium titanate (BST), on a substrate through reactive sputteπng. The apparatus composes a physical vapor deposition chamber having a pulsed direct current power source supplying a first bias to a target and a second bias to the substrate being processed in the chamber The power source is preferably an asymmetric bipolar pulsed direct current power source that supplies an electrical waveform compπsing a deposition voltage and a neutralization voltage. The deposition voltage compπses a negative voltage which attracts the argon ions toward trje target, and thus causing sputteπng of the target mateπal. The neutralization voltage compπses a positive voltage that causes a charge neutralization and eliminates arcmg and micro-arcing on the target surface. Preferably, the first bias is synchronized with the second bias to enhance the film properties of the deposited material and to provide consistent conformal step coverage of high aspect ratio features.

One aspect of the invention provides separate gas inlets for the processing gases. Preferably, a first gas inlet introduces a plasma generating gas through the top portion of the chamber, and a second gas inlet introduces a reactive gas adjacent the substrate surface to react with the sputtered material to form the HDC film on the substrate. For deposition of BST, argon is preferably introduced through the top portion of the chamber to provide ions that cause sputtering from the target while oxygen is introduced adjacent the substrate surface to react with the sputtered material to form BST on the substrate surface.

Another aspect of the invention provides a shield having a floating potential with respect to ground that surrounds the processing region between the target and the substrate to increase the plasma density in the processing region and increase the deposition rate of the process. The present invention preferably provides low contaminant particle generation during processing, high deposition rate, high throughput, excellent (void-less) gap-fill of high aspect ratio features, elimination of arcing and micro-arcing, and better crystal quality and grain orientation of the resulting BST film.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.

It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

Figure 1 is a cross sectional view of a prior art PVD chamber for depositing a BST film.

Figure 2 is a cross sectional view of a PVD chamber for forming a HDC film according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Figure 2 is a cross sectional view of a physical vapor deposition chamber for forming a film according to the invention. The PVD chamber 100 generally comprises a chamber enclosure 102, a target 104, a substrate support 106, a gas inlet 108 and a gas exhaust 110. The chamber enclosure 102 includes a chamber bottom 112 and a chamber side wall 114. A slit valve 115 is disposed on a chamber side wall 114 to facilitate transfer of a substrate 116 into and out of the PVD chamber 100. The substrate support 106 is disposed on a substrate support lift assembly 118 through the chamber bottom 112. Typically, a heater (not shown) is incorporated within the substrate support 106 to heat the substrate 116 to a particular temperature during processing. Preferably, the substrate support 106 is made of stainless steel, and the heater comprises a platinum/rhodium heater coil. However, other suitable materials are contemplated by the invention. The substrate support lift assembly 118 moves the substrate support 106 vertically between a substrate transfer position and a substrate processing position. A lift pin assembly 120 lifts the substrate 116 off the substrate support 106 to facilitate transfer of the substrate 116 between the chamber and a robot blade used to transfer the substrate into and out of the chamber. The target 104 is disposed in the top portion of the chamber enclosure 102. Preferably, the target 104 is positioned directly above the substrate support 106. The target 104 generally comprises a backing plate 122 supporting a plate of sputterable material 124. The composition of the sputterable material generally corresponds to the composition of the resulting film. For deposition of BST, the sputterable material 124 is a combination of barium, strontium and titanium, typically about 25% Ba, about 25% Sr and about 50% Ti, which corresponds to the resulting BST film comprising (Ba_{o j}Sr_{o s}^iO_j. The backing plate 122 includes a flange portion 126 that is secured to the chamber enclosure 102 during operation. Preferably, a seal 128, such as an o-ring, is provided between the flange portion 126 of the backing plate 122 and the chamber enclosure 102 to enable a vacuum environment to be established and maintained in the chamber during processing. A rotating magnet assembly 130 is disposed above the backing plate 122 to provide magnetic field enhancement that attracts ions from the plasma toward the target sputtering surface to enhance sputtering of material. The magnetic field enhances the ionization by confining more electrons, and thus, providing more ions to contribute and increase sputtering from the target.

The backing plate 122 according to the invention has an increased thickness compared to known backing plates. Generally, current backing plates have about the same thickness (i.e., ±10%) as the initial thickness of the sputterable material on the target. For example, a typical target has a backing plate thickness of about 0.33 inches (8.38 mm) and a sputterable material thickness of about 0.35 inches (8.89 mm). The invention increases the backing plate thickness to about twice (i.e., 180% to 220%) of the current backing plates while retaining the same sputterable material thickness. For example, the invention provides a target having a backing plate thickness of about 0.71 inches (18.0 mm) and a sputterable material thickness of about 0.35 inches (8.89 mm). By increasing the thickness of the backing plate 122 to about twice the thickness of known backing plates, a more uniform magnetic field results across the target sputtering surface because the magnets are positioned farther away from the target sputtering surface and the magnetic field gradient is reduced. A more uniform magnetic field provides a more uniform ionization that leads to a more uniform sputtering and erosion of the target. With a uniform and controlled erosion of the target, the target material sputtered or the species ejected from the target are controlled to be the same ratio as the percentage composition of the species of the target. The thicker backing plate, according to the invention, also provides better (lower) deflection compared to known backing plates. Deflection is defined as the maximum flex (i.e., bending) of the backing plate when exposed to a particular pressure. For example, a typical backing plate (8.38 mm thick) under a pressure of 3 kgf/cm^: exhibits a deflection of 1.100 mm while the backing plate of the invention (18.0 mm thick) exhibits a deflection of 0.337 mm. Lower deflection prevents cracking of the sputterable material on the target which has a lower yield point compared to the backing plate metal. Furthermore, a thicker backing plate provides stronger mechanical strength to the target as a whole that reduces the risk of mechanical breakdown or cracking of the target because the target as a whole is stronger. A lower shield 132 is disposed at the top portion of the chamber to define a processing region in combination with the support member and the target and also shields the interior surfaces of the chamber enclosure 102 outside of the processing region from deposition. The lower shield 132 extends from the upper portion of the chamber side wall 114 to a peripheral edge of the substrate support 106 in the processing position. A clamp ring 134 is removably disposed on an inner terminus 136 of the lower shield 132. When the substrate support 106 moves into the processing position, the inner terminus 136 of the lower shield 132 surrounds the substrate support 106, and a peripheral portion 138 of the substrate 116 engages an inner terminus 139 of the clamp ring 134 and lifts the clamp ring 134 off the inner terminus 136 of the lower shield 132. The clamp ring 134 serves to clamp or hold the substrate 116 as well as shield the peripheral portion 138 of the substrate 116 during the deposition process. A plurality of substrate contact pads 141 are evenly distributed about the under surface of the inner terminus 139 of the clamp ring 134 to contact the upper surface of the substrate 116. Thus, a plurality of gaps exist between adjacent contact pads 141 to allow passage of a gas between the under surface of the clamp ring 134 and the upper surface of the substrate 116. Alternatively, instead of a clamp ring 134, a shield cover ring (not shown) is disposed above an inner terminus of the lower shield. When the substrate support moves into the processing position, the inner terminus of the shield cover ring is positioned immediately above the peripheral portion of the substrate to shield the peripheral portion of the substrate from deposition. However, the shield ring preferably does not contact the substrate to allow passage of a gas between the under surface of the shield cover ring and the upper surface of the substrate. Preferably, an upper shield 140 is disposed within an upper portion of the lower shield 132 and extends from the upper portion of the chamber side wall 1 14 to a peripheral edge 142 of the clamp ring 134. Preferably, the upper shield 140 compπses a material that is similar to the materials that comprise the target, such as titanium and other metals. The upper shield 140 according to the invention has a floating potential with respect to ground. The upper shield 140 provides an increased ionization of the plasma as compared to a grounded upper shield by preventing the drain of electrons due to the shield and causes an increased ionization toward the edge of the target. The increased plasma density due to the increased ionization enhances sputtering near the edge of the target, resulting in a more uniform erosion across the target. Also, the increased ionization provides more ions that are available to impact the target 104, and a higher deposition rate is achieved because of the increased sputtering from the target 104. The higher deposition rate leads to a higher throughput because less time is required to deposit the BST film using the same power density.

A gas inlet 108 disposed at the top portion of the chamber enclosure 102 introduces a processing gas into a processing region 146 through a gap between the target 104 and the upper shield 140. The processing region 146 is defined by the target 104, the substrate 116 disposed on the substrate support 106 in the processing position and the upper shield 140.

According to the invention, for deposition of a BST film, argon is introduced through the gas inlet 108 as the process gas source for the plasma while oxygen is introduced through a second gas inlet 148 disposed adjacent the substrate 116 for the formation of the BST film.

Preferably, the second gas inlet 148 is disposed within the substrate support 106. However, the second gas inlet 148 can also be disposed in another part of the chamber to provide a reactive gas to the substrate deposition surface. The second gas inlet 148 is connected to a gas passage extending through the stem of the substrate support 106 and delivers the second gas through channels on the surface of the substrate support 106. To reach the top surface of the substrate, the second gas travels around the edge of the substrate and through a gap between the undersurface of the clamp ring 134 and the top surface of the substrate. Thus, the second gas is concentrated near the top surface of the substrate to react with the sputtered material from the target and complete the reaction for reactive sputtering. By delivering the reactive gas near the substrate surface and away from the target sputtering surface, the invention significantly reduces the reaction of the reactive gas on the target sputtering surface and the resulting formation of dielectric material on the target sputtering surface. In the case of BST deposition, by introducing oxygen adjacent to the substrate 1 16, oxygen is less likely to react on the target sputteπng surface and form a BST film on the target sputteπng surface that may lead to stored charges on the target surface that results in arcing and contaminant particle generation as well as damage to the target itself. To supply a bias to the target 104, a pulsed direct current (PDC) power source 152 is electπcally connected to the target 104. Preferably, the PDC power source 152 is an asymmetπcal bipolar PDC power source that supplies a bias waveform compnsing a repeating cycle compnsing a deposition voltage (negative) and a neutralization voltage (positive). The deposition voltage is preferably between about -100 volts and about -700 volts for about 60% to about 100% of the cycle. The neutralization voltage or a reverse discharge voltage is preferably between about 30 volts to about 80 volts for about 0% to about 40% of the cycle. The bias waveform frequency is preferably between about 50 KHz and about 250 KHz with each cycle lasting between about 4 μs and about 20 μs. Even more preferably, the bias waveform is a 200 KHz waveform having a duty cycle comprising a deposition voltage of about -358 volts for about 3.75μs and a neutralization voltage of about +80 volts for about 1.25 μs.

The PDC power source 152 is also electπcally connected to the substrate support 106 to supply a second bias to the substrate support 106 and the substrate 116 positioned thereon during the deposition process. Preferably, the PDC power source 152 provides a master and slave configuration that provides corresponding first and second biases. The bias applied to the substrate 1 16 is typically in the range between about 0 watts and about 300 watts during the deposition process. Preferably, the PDC power source 152 supplies synchronized biases to the target 104 and the substrate support 106, respectively, such that the cycle/voltages change correspondingly. Because the PDC power source 152 provides a neutralization voltage (i.e., a positive voltage) to the target 104, the positive charge that accumulates on the target 104 during the deposition period is released and repelled from the sputtering surface of the target 104. The positive charge accumulated on the target is repelled because the target is now also positive during the neutralization period. Thus, no excess positive charge accumulates on the target, and arcing from the target 104 to the upper shield 140 or the chamber enclosure 102 is eliminated. To further reduce contaminant generation, no RF power source is utilized so that the micro-arcing phenomenon is also eliminated from the PVD chamber of the invention. As a result, contaminant particle generation is minimized, and defects forming on the substrate due to contaminant particles has been significantly reduced to less than 30 (compared to the pπor art PVD BST chamber that generates more than 10,000 defects on the substrate).

In operation, the substrate 1 16 is transferred on a robot blade (not shown) into the chamber 100 through the slit valve 1 15 and positioned above the substrate support 106. The lift pin assembly 120 moves up and lifts the substrate 1 16 above the robot blade, and the robot blade retracts out of the chamber 100. The slit valve 115 closes to provide a sealed environment, and the chamber is pumped down by a vacuum pump (not shown) connected to the gas exhaust 110. The substrate support 106 is moved up by the substrate support lift assembly 118 into the process position. As the substrate support 106 moves up, the substrate 116 is positioned onto the substrate support 106 and subsequently engages the clamp ring 134. Argon is then introduced into the chamber through the gas inlet 108, and a plasma is struck within the processing region 146 by applying a first and second bias from the PDC power source 152 to the target 104 and the substrate support 106, respectively. Alternatively, argon may also be introduced into the chamber through the second gas inlet 148 disposed within the substrate support 108 as well. At the same time, oxygen is introduced adjacent the substrate 116 through the second gas inlet 148 disposed within the substrate support 106. The sputtered material (combination of Ba, Sr and Ti) from the target 104 react with the oxygen ions and is transferred onto the substrate 116 to form a BST film. Preferably, the pressure within the processing region 146 is maintained between about 10 mTorr and about 30 mTorr while the pressure between the outside of the lower shield 132 and the chamber enclosure is maintained between about 3 mTorr and 10 mTorr. The temperature of the substrate 116 during processing is preferably maintained at about 550°C.

Example

A substrate is transferred into an evacuated PVD chamber and positioned on the substrate support after the substrate has been oriented and degassed in an orientation/degas chamber. The substrate support moves to a processing position, and the processing gases are introduced into the chamber. Argon is introduced through the first gas inlet at about 95 seem and also through the second gas inlet on the substrate support at about 15 seem. Oxygen is also introduced through the second gas inlet at about 15 seem. Once the chamber pressure is stabilized to about 6 mTorr, the PDC power source is turned on to supply a first bias to the target of about 1000 W at 200 KHz at about 25% duty cycle, which translates to a cycle of 5 μsec with the negative voltage on for 3.75μsec (sputtering) and the positive voltage on for 1.25 μsec (charge neutralization). The PDC power source also supplies a second bias at about 300 W to the substrate support that is synchronous with the first bias. The deposition process is maintained for about 90 seconds at a deposition rate of about 200 A/min to achieve a deposition thickness of about 300 A. The power is then shut off, and the processing gases are exhausted from the chamber before the substrate is transfeπed out of the chamber.

The advantages of the present invention includes low contaminant particle generation during processing, higher deposition rate, higher throughput, excellent (void-less) gap-fill of high aspect ratio features, elimination of arcing and micro-arcing, and better crystal quality and grain orientation of the resulting BST film. For example, with the processing conditions outlined in the example, the chamber condition remains clean after a 1200 substrate run, and defects forming on a substrate due to contaminant particles has been significantly reduced to less than 30. The target life time is expected to be greater than 1000 KWH, and the process kit lifetime is expected to be greater than 250 KWH. The throughput (substrate per hour per chamber) increases significantly along with the corresponding increase in the deposition rate to greater than about 200 A/min. Also, the composition uniformity of the deposited film is controlled to within 2% on a substrate and within 1% between different substrates of the same run. Although the invention is described as applied to the formation of a BST film, the invention contemplates applications to other films formed using oxygen as the reactive gas, including lanthanum strontium cobalt oxide (LSCO), lead zirconium titanate (PZT), strontium bismuth tantalate (SBT), silicon oxide (SiO₂), aluminum oxide (Al₂O₃). The invention also contemplates applications to films formed using nitrogen as the reactive gas, including silicon nitride and aluminum nitride.

While foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basis scope thereof, and the scope thereof is determined by the claims that follow.

Claims

CLAIMS:

1. An apparatus for depositing a material onto a substrate, comprising: a) a physical vapor deposition (PVD) chamber comprising: i) a target disposed in the chamber; ii) a substrate support member disposed in the chamber; iii) a lower shield surrounding a region between the target and the substrate support; iv) a first gas inlet disposed between the target and the shield; and v) a gas outlet connected' to the chamber; and b) a pulsed direct current (PDC) power source supplying a first bias to the target and a second bias to the substrate support member.

2. The apparatus of claim 1 wherein the PDC power source provides a deposition voltage and a reverse discharge voltage.

3. The apparatus of claim 1 wherein the PDC power source provides a waveform voltage comprising a deposition voltage between about -100 volts and about -700 volts for between about 60% and about 100% of a waveform cycle and a reverse discharge voltage between about +30 volts and about +80 volts for between about 0% and about 40% of a waveform cycle.

4. The apparatus of claim 3 wherein the waveform cycle is between about 4 μs and about 20 μs.

5. The apparatus of claim 1 wherein the PVD chamber further comprises an upper shield surrounding a region between the target and the substrate support.

6. The apparatus of claim 5 wherein the upper shield is grounded.

7. The apparatus of claim 5 wherein the upper shield has a floating potential with respect to ground.

8. The apparatus of claim 1 wherein the substrate support includes a second gas inlet.

9. The apparatus of claim 8 wherein the first gas inlet is connected to an argon gas supply and the second gas inlet is connected to an oxygen gas supply.

10. The apparatus of claim 9 wherein the target comprises a material selected from the group consisting of silicon, aluminum, a combination of barium, strontium and titanium, a combination of lanthanum, strontium and cobalt, a combination of lead, zirconium and titanium, and a combination of strontium, bismuth and tantalum.

11. The apparatus of claim 1 wherein the first gas inlet is connected to an argon gas supply and the second gas inlet is connected to a nitrogen gas supply.

12. The apparatus of claim 1 wherein the target comprises a material selected from the group consisting of aluminum and silicon.

13. The apparatus of claim 1 wherein the target comprises a backing plate and a sputterable material, wherein the backing plate is about twice as thick as the sputterable material.

14. A method for forming a film on a substrate, comprising: a) positioning the substrate on a substrate support member in a chamber; b) introducing a first gas into the chamber; c) introducing a second gas into the chamber, d) supplying a first bias to a target in the chamber and a second bias to the substrate support member using a pulsed direct current (PDC) power source; and e) sputtering a material from the target.

15. The method of claim 14 wherein the PDC power source provides a deposition voltage and a reverse discharge voltage.

16. The method of claim 14 wherein the PDC power source provides a waveform voltage comprising a deposition voltage between about -100 volts and about -700 volts for between about 60% and about 100% of a waveform cycle and a reverse discharge voltage between about +30 volts and about +80 volts for between about 0% and about 40% of a waveform cycle.

17. The method of claim 16 wherein the waveform cycle is between about 4 μs and about 20 μs.

18. The method of claim 14 wherein the target comprises a combination of barium, strontium and titanium.

19. The method of claim 18 wherein the first gas is argon and the second gas is oxygen. .

20. The method of claim 14 further comprising: f) surrounding a region between the target and the substrate using a shield having a floating potential with respect to ground.

21. The method of claim 14 wherein the second gas is introduced through a gas inlet in a substrate support member.

22. The method of claim 14 wherein the first bias and the second bias are synchronized.