Low temperature zirconia based thermal barrier layer by PVD
View Patent ↗Formation of a zirconia based thermal barrier layer is described. In accordance with the present invention, a thermal barrier layer composed of zirconia or an allow of zirconia is presented. An advantageous layer might be composed of zirconia or an alloy of zirconia with silica having improved properties. In some embodiments, such a zirconia layer might be deposited with a fraction of it's zirconia in a metallic state. Such a fraction, particularly if it were very low, would act to nucleate crystalline grains of silicon during the recrystallization phase of excimer laser melting due to the formation of point defects of zirconium silicide or other nucleating compound or formation. Heat treating the Zirconia layer anneals the Zirconia layer so that it can act as a gate oxide.
1. A method of forming a layer, comprising:
forming a conductive ceramic zirconia target;
depositing a zirconia layer on a low temperature material in a physical vapor deposition (PVD) chamber from the target, wherein the layer is deposited by:
applying pulsed direct current (DC) power to a target cathode of the physical vapor deposition (PVD) chamber through a band rejection filter that rejects radio frequency (RF) power at a frequency, and
applying an RF bias power at the frequency to a substrate,
wherein the low temperature material is a material that is damaged at a melting temperature of amorphous silicon.
2. The method of claim 1 , wherein forming the target includes
mixing zirconia powder with between 8 and 12% yttria powder; and
isostatic pressing the mixed powder.
3. The method of claim 1 , wherein forming the target includes
mixing zirconium metal with about 8 to about 12% yttria metal powder; and
hot isostatic pressing the mixed powder.
4. The method of claim 3 , wherein depositing a zirconia layer includes
applying between about 4 and about 8 kW of 200 MHz pulsed DC power on the target;
applying between about 3 and about 6 mTorr of system pressure to the PVD chamber;
applying about 200 to about 600 Watts at 2 MHz of bias power to the substrate on which the zirconia layer will be deposited.
5. The method of claim 4 , further including
adding between about 60 and about 80 sccm of oxygen to the PVD chamber; and
adding between about 40 and about 20 sccm of Argon to the PVD chamber, wherein the total gas flow is about 100 sccm.
6. The method of claim 1 , wherein the low temperature material is a glass or a plastic material.