Method for Manufacturing ScAlN Target

Abstract

The invention relates to a method for producing a scandium aluminum nitride (ScAlN) target body for pulsed laser deposition (PLD), which includes the steps of: providing a scandium aluminum alloy body; pulverizing the scandium aluminum alloy body into scandium aluminum particles; nitridizing the scandium aluminum particles into scandium aluminium nitride particles; and hot pressing the scandium aluminum nitride particles into a scandium aluminum nitride target body.

Claims

1. A method for producing a scandium aluminum nitride (ScAlN) target body for pulsed laser deposition (PLD), which method comprises the steps of: providing a scandium aluminum alloy body; pulverizing the scandium aluminum alloy body into scandium aluminum particles; nitridizing the scandium aluminum particles into scandium aluminium nitride particles; and hot pressing the scandium aluminum nitride particles into a scandium aluminum nitride target body.

2. The method according to claim 1, wherein the nitridizing of the scandium aluminum particles comprises the step of feeding the scandium aluminum particles in a gas stream of nitrogen or ammonia (NH.sub.3), while maintaining a temperature of the ammonia gas and scandium aluminum particles mixture of over 500° C.

3. The method according to claim 1, wherein the scandium aluminum nitride particles are hot pressed in an isostatic hot press.

4. The method according to claim 1, wherein the scandium aluminum nitride particles are hot pressed at a pressure of over 90 MPa, preferably at a pressure of 150-250 MPa.

5. The method according to claim 1, wherein the scandium aluminum nitride particles are hot pressed at a temperature of over 1600 degree C., preferably at a temperature of 1750-2200 degree C.

6. The method according to claim 1, wherein the scandium aluminum alloy body is pulverized by grinding said body.

7. The method according to claim 1, wherein after the pulverizing step the scandium aluminum particles have a particle size smaller than 10 micrometer, more preferably smaller than 1 micrometer.

8. The method according to claim 1, wherein the scandium aluminum nitride target body comprises at least 20 at % scandium.

9. The method according to claim 1, wherein the scandium aluminum nitride particles are hot pressed into a scandium aluminum nitride target body with a relative density of above 80%, more preferably above 98%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] These and other features of the invention are schematically shown in the accompanying drawings.

[0030] FIG. 1 shows schematically the steps of an embodiment of the method according to the invention.

[0031] FIGS. 2A and 2B show the difference between a target body according to the prior art and a target body produced with the method according to the invention in a PLD process.

DESCRIPTION OF THE INVENTION

[0032] In FIG. 1 first a scandium aluminum (ScAl) alloy body 1 is provided. This ScAl body 1 is then pulverized, for example by grinding, into a powder 2 of scandium aluminium particles.

[0033] The ScAl powder 2 is then fed to a fluidized bed reactor 3, in which ammonia (NH.sub.3) is pumped by a pump 4, while maintaining the temperature at for example 500° C. This allows for the particles of the ScAl powder 2 to be nitridized into scandium aluminium nitride particles.

[0034] After a certain amount of time, the nitridized particles are removed from the fluidized bed reactor 3 and arranged in a flexible mould 5, which is placed in a pressure vessel 6, which is supplied with a suitable pressure P, such that the mould 5 is subjected to an isostatic pressure. As a result the scandium aluminium nitride particles in the mould 5 will be compressed into a target body 7.

[0035] FIG. 2A shows schematically a target body 10 according to the prior art with separate scandium nitride particles 11 and aluminum nitride particles 12. Due to the different type of particles 11, 12 voids 13 are present in the target body 10.

[0036] When such a prior art target body 10 is irradiated with a laser beam 14 only part of the energy is absorbed by the particles 11, 12. But due to the difference in bandgap between scandium nitride and aluminum nitride, the scandium nitride particles 11 will more easily be transferred into a plasma than the aluminum nitride particles 12, which tend to break loose from the target body 10 as undesired droplets 15.

[0037] FIG. 2B shows schematically a target body 20 produced with the method according to the invention. The target body 20 is composed out of a single type of particles 21, in particular scandium aluminum nitride particles. As a single type of particles can be better compressed into a target body, the density of the target body 20 is considerably higher than the prior art target body 10. This already improves the absorption of the laser beam 22, which generates the plasma plume 23.

[0038] As scandium aluminum nitride has a bandgap lower than aluminum nitride, the laser beam 22 can more easily, more reliably and without generation of droplets transfer the target body material into a plasma plume 23.