A Vertically Integrated Approach to Sapphire Production

One of the things we take pride in at Rubicon Technology is our end-to-end manufacturing capabilities.

By having state-of-the-art facilities that support vertical integration, starting with the raw material aluminum oxide, we’re able to eliminate excess costs for our customers, and provide greater quality control to ensure the delivery of defect-free sapphire with diameters of 2, 4, 6, and soon, 8 inches.

This ultimately benefits LED chip manufacturers since high-quality, large-diameter wafers provide a higher yield and reduce costs of LEDs for commercial and residential use. Improved cost and luminous efficiency are fundamental to the acceleration of LED adoption in the marketplace — and continue to be strategic priorities for Rubicon.

The infographic below explains the basics of the six-step process of transforming sapphire into an LED module. Rubicon carries out steps 1 through 4 of the process — from crystal growth to wafer processing — before turning over to LED chip manufacturers.

We should also note that Rubicon recently started providing patterned sapphire substrates (PSS) to increase the LEDs’ light output by up to 30 percent. PSS is added directly prior to the epitaxial growth process.

The latter part of the process, after drilling, is primarily carried out in Rubicon’s facility in Malaysia. This facility enables Rubicon to reduce costs associated with making a 6-inch wafer.

For more info on the benefits of a vertically integrated approach, check out pages 50-55 of Compound Semiconductor’s March 2013 edition.

Sapphire Demystified

A look at Rubicon Technology's sapphire

A look at Rubicon Technology’s sapphire

There has been so much hype and misinformation about sapphire lately, particularly surrounding sapphire covers or faceplates for smartphones, that we thought we’d review some basic info about commercial sapphire.

  • “Sapphire glass”

There really isn’t any such thing as sapphire “glass.” Sapphire is not a kind of glass; it’s a very hard monocrystalline material. The proper way to reference the clear layer of stuff that may soon cover the screen of your smart phone is as a “sapphire cover” or “sapphire faceplate.” Glass is made of silica or sand, and sapphire is made from aluminum oxide. The two materials have very different physical properties. So, glass isn’t really the right descriptor.

  • Sapphire is unbreakable.

Well, no. That’s not really accurate. A thin piece of sapphire can shatter, similarly to glass or a piece of gorilla glass. Sapphire is the second hardest material on Earth (after the diamond). As such, a thin slice of sapphire will shatter. What is sapphire good at? Sapphire is scratch resistant. That’s one of the main reasons why smartphone vendors are interested in sapphire for applications in lenses and fingerprint scanners.

  • Sapphire is blue.
Sapphires come in a range of colors.

Sapphires come in a range of colors. The purest sapphires are clear.

Yes and No. Sapphire, also called corundum, comes in a range of colors. The purest form of sapphire is clear.  Sapphire is a crystal made from Aluminum Oxide (Al2O3). Natural sapphire forms over thousands of years in the earth, but comes in different colors due to impurities such as minerals or other conditions (like humidity or radiation). Rubies are made of aluminum oxide and are actually sapphires. They are red because the crystal contains impurities in the form of the mineral chromium, making the crystal red. Sapphire gemstones get their blue hue from iron and titanium. Yellow sapphires get their color from a combination of iron and radiation (interesting).  The commercial sapphire that’s now being used in consumer electronics is very pure, so it’s colorless.

  • Sapphire in LEDs and smart phones is from blue sapphire gemstones.

No. The sapphire that is used in LEDs and smartphones is grown in a commercial setting using one of few processes – the Verneuil Method, Kyropoulous Method, Heat Exchanger Method, Czochralski Method and Edge-Defined Film-Fed Growth Method. Each method has its differences, but they produce a single crystal of clear sapphire that is fabricated (cut and polished) into a sapphire substrate used in an LED or into a lens or faceplate for optical uses like smart phones.