Introduction
One of the best heat conductor materials you can find globally today is Aluminum Nitride. Not only does aluminum nitride conduct heat excellently in various applications, but it also has the required dielectric strength to be an exceptional electrical insulator. Little wonder, it’s gaining so much popularity and widespread usage in so many industries. In today’s article, you will learn about the unique properties, synthesis, and applications of this aluminum nitride material and aluminum nitride heaters. You will also see how aluminum nitride is manufactured, the challenges you may encounter, and the current market trends of aluminum nitride material.
What is Aluminum Nitride Used For?
Aluminum Nitride is an exceptionally heat-resistant ceramic material composed of Aluminum and Nitrogen. It has a chemical formula AlN and a small atomic mass that is covalently bonded. This crystalline colourless compound is regarded as a top-notch electrical insulator and semiconductor material. The truth is, you can’t talk about electrical insulation and heat conductivity today without mentioning AlN ceramic materials. They are one of the best materials you can use when it comes to applications involving high-power electronics, heaters, and heat sinks because they can spread and dissipate heat at an impressive rate, notwithstanding the temperature they are subjected to.
AlN is a solid nitride of aluminum that exists mainly in the hexagonal wurtzite crystal form and the metastable cubic zinc blende phase. At room temperature, this wurtzite aluminum nitride (w-AlN) has a band gap of 6 eV that enables it to work efficiently at deep ultraviolet frequencies for optoelectronics. The simple yet powerful atomic bonding structure of AlN is one of the main reasons it has a large thermal conductivity of 320 w/mk-1. Impurities like oxygen reduce the thermal conductivity of AlN, while doping boosts the material’s electrical conductivity. Interestingly, you can use aluminum nitride to reduce the rate of power consumption in semiconductors by protecting and coating them with it.
Properties of Aluminum Nitride Materials
Aluminum nitride ceramic material has a lot of unique properties that make it outstanding and useful in so many sectors. Here are some of them:
-
High thermal conductivity of 321 W/mk-1
-
Excellent electrical insulator
-
Ability to perform optimally even at high temperatures.
-
Low thermal expansion coefficient of 5.6 x 10-6K-1.
-
High compressive strength, hardness, and thermal shock resistance.
-
High melting point of about 2,200°C.
-
High wide bandgap of 6 eV, second only to Beryllia.
-
Exhibits spontaneous polarization due to the hexagonal wurtzite crystal structure.
-
High dielectric strength with a dielectric constant of 8.6.
-
High ductility and elastic limit of 310 GPa.
-
Impressive transparency window of 0.2μm - 13.6μm.
-
Smooth compatibility with Complementary Metal Oxide Semiconductor (CMOS).
-
Strong resistance to molten metals, chlorides, salts, and alkalis.
-
Has a density of 3.32g/cm³.
-
Possesses a specific heat capacity of 780 J.Kg/K-1.
Synthesis of Aluminum Nitride Material
Briegleb and Geuther were the first scientists to synthesize (produce) Aluminum Nitride in 1862, and since then, so many industries now synthesize this all-important semiconductor material. Now, you can synthesize aluminum nitride material in three major ways, which are:
Carbothermal reduction of Alumina:
This is the most common way to produce highly pure and water-resistant aluminum nitride. In this method, aluminum hydroxide or alumina is heated to a temperature reaching 1,750°C under a nitrogen gas stream and carbon, which acts mainly as the reducing agent.
Direct Nitridation of Aluminum:
AlN can be synthesized by directly reacting aluminum powder and nitrogen gas under controlled temperature and nitrogen gas flow rate. The temperature range for heating is 650°C.
Chemical Vapor Deposition (CVD):
This method works best for temperatures within the range of 650°C - 750°C. In this method, under certain conditions like good vacuum, aluminum chloride compound (AlCl3) is nitrided with ammonia gas or nitrogen to produce AlN.
Applications of Aluminum Nitride Materials
The applications of aluminum nitride ceramic material cut across so many industries, some of them are:
Electronics Industry
You can use aluminum nitride to produce heat sinks for high-power electronics like LED, computer, or mobile devices that require fast heat dissipation. It can also be used for many other microelectronics components that require high densities. RF Filters, electrical insulators, and acoustic wave sensors all make use of AlN ceramic material.
Semiconductors
Aluminum nitride substrates boast a very unique cooling ability that you can rarely find in other semiconductor materials. No surprise, more semiconductor industries are manufacturing heating plates, lasers, clamp rings, microwaving devices, and chip carriers from AlN ceramic material.
Military
You can use AlN ceramic materials to produce military weapons and vehicles like armoured tanks, abrasives, high-grade bullets, among others, due to their high specific heat capacity and ability to withstand thermal shock.
Refractory
Some industries now exploit the refractory property of AlN to make furnace linings, crucibles, and thermal insulators since aluminum nitride can comfortably handle harsh temperatures and perform optimally without losing form.
Transportation and Automotive Industry
Radar systems, power modules, aerospace devices, automobile spare parts, and engines can all be produced from AlN ceramic materials.
Aluminum Nitride Manufacturing Process
Several processes can be used to manufacture aluminum nitride parts, depending on the product specifications, cost of production, and the intended application. Some of these aluminum nitride manufacturing processes include:
Cold Isostatic Pressing (CIP)
You can manufacture aluminum nitride parts through this process by applying equal pressure on all sides of the AlN powder before you finally proceed to aluminum nitride machining. This method produces high-performance aluminum nitride materials.
Ceramic Injection Molding (CIM)
In this method, you are to mix your AlN powder with the aid of an organic carrier (binder) and pour it into any mould of your choice (depending on the shape you want). Thereafter, you remove the binder and, under high temperatures and pressure, sinter it into the shape you want. Sintering is done to ensure the AlN material has a firm density.
Low-Pressure Powder Injection Molding
If you want to save costs and still produce a complex-shaped AlN material, then this method is the best for you. It is very similar to the CIM method, only that it is done at low pressures. However, your AlN material can get cracked if you don’t remove the organic carrier properly.
Tape Casting
This method gives you dense aluminum nitride parts that boast of a high compatibility with metal electrodes. In this method, first of all, you properly mix AlN powder, dispersant, organic carrier, and a plasticizer. Then, cast it against a support surface, you would get a smooth green tape which you dry and sinter for 2-3 minutes under temperatures reaching 470°F.
Precision Machining
This aluminum nitride manufacturing method involves using high-precision CNC machines to grind and shape AlN. However, manufacturing of aluminum nitride heating plates is becoming a challenging process due to the extreme hardness of the AlN ceramic material. Excessive vibrations while machining can damage or greatly hamper the effectiveness of your cutting tools and machines because of the high compressive strength of these aluminum nitride parts. As a result, you can use a more effective tool like PolyCrystalline Diamond (PCD) for machining aluminum nitride plates mainly because of the Diamond component in them. Aside from the tough, hard nature of aluminum nitride plates, another challenge manufacturers face while trying to machine aluminum nitride heating plates is the material’s high thermal conductivity and brittleness, meaning it could crack under heavy mechanical stress if it’s not handled properly.
Characteristics of Aluminum Nitride Heaters
Aluminum nitride heaters are heating elements produced primarily from aluminum nitride material. The several unique thermal and electrical properties of AlN make them capable of handling any type of high temperatures, as well as excellent heat transfer in any application you deem fit. Some of the properties of AlN heaters are:
-
Maximum working temperature of 1,000°C.
-
They possess a heating speed of about 115°C per second.
-
They have a density of 3.26g/cm³.
-
They have a thermal conductivity of 220w/mk-1
-
Maximum wax density of 155w/cm²
-
They possess a thickness reaching about 3mm
Applications of Aluminum Nitride Heaters
You can use aluminum nitride for a variety of applications, like:
Optoelectronics
Due to their ability to manage high temperatures and control thermal energy, you can use aluminum heaters in optoelectronics to produce laser diodes, LED lights, and other microelectronics.
Semiconductor Industry
You can use aluminum nitride heaters for complex tasks such as epitaxy and Physical Vapor Deposition (PVD), which require wafer processing. You can also test for measuring equipment in semiconductor devices.
Medicine
You can also use aluminum nitride heaters in medicine for DNA amplification. These AlN heaters are used in medical laboratory science to produce equipment for several high-profile tests like DNA and Polymerase Chain Reaction (PCR), because of their precise temperature control.
Production of Hot Plates
These aluminum heaters can be used to produce the hot plates you use to heat your food at home. It can also be used to make industrial heating plates.
Chemistry
You can use AlN heaters to produce equipment that requires very high temperatures to function optimally. Some of this equipment can be used in chemistry for chromatography, mass spectrometry, etc.
Current Market Trends of Aluminum Nitride
As of 2023, the global market size of aluminum nitride was a little over $151 million. If you followed the market trends in 2024, you would see a notable increase of about 11.5% as the market rallied to $168 million. Market analysts have said that with a Compound Annual Growth Rate (CAGR) of 5.6%, you should be expecting a market value of over $245 million by 2030 due to increased global demand and fierce market competition. North American company Surmet has since be en a key player in large scale AlN manufacturing and supplies. Here, at ggsceramics, you can also purchase high-quality and affordable aluminum nitride heaters, aluminum nitride ceramic materials, and products of your choice.
Frequently Asked Questions
Is Aluminum Nitride (AlN) an explosive material?
No, ordinarily, AlN is a chemically inert compound; however, in the presence of chlorinated vapors and acids, it can explode.
Is aluminum nitride toxic?
Yes, AlN can cause you serious harm if you swallow, ingest, or inhale it. It can either cause skin and eye irritation or damage the bone marrow and lungs.
Which is a better semiconductor material between Aluminum Nitride and Silicon Carbide?
Semiconductor materials for high-power electronics are more effective when there’s efficient thermal conductivity and heat dissipation. Obviously, aluminum nitride material beats other semiconductors to this regard, due to its ultra-wide band gap, meaning it gets ahead of Silicon Carbide (SiC) in this regard.
Conclusion
Aluminum Nitride ceramic material is steadily breaking new ground in the semiconductor industry. Ranging from aluminum nitride plates to aluminum nitride heaters and heat sinks, the applications of AlN have so far cut across several industries; It’s a good sector to invest in, and certainly, the future of semiconductors is brightly secured with aluminum nitride firmly in the driving seat.