Krypton import prices have reached an all-time high. As it accounts for the majority of global NAND flash memory, this is expected to weigh on NAND production costs.

According to import and export statistics from the Korea International Trade Association, as of April 2021, the average import price of krypton this year was $320 per kilogram, a 61% increase from the previous year. This is the highest price ever recorded.

The price of krypton continues to rise, averaging $38 per kg in 2018, rising 111% year-on-year to $82 per kg in 2019, and 143% year-on-year to $199 per kg in 2020.

Import volumes are also continuing to increase. In 2021, krypton imports amounted to 32,780 kg, a 31.3% increase over the same period last year.

This is equivalent to 43.6% of the 69,476 kg in 2020, and the total import volume this year is expected to increase significantly compared to last year.

This price increase is analyzed to be due to the explosive increase in demand while production is limited.

Krypton, which is only about one millionth of the atmosphere, is produced through fractional distillation in an air separation unit (ASU), just like other rare gases such as xenon and neon. However, as the lighting industry, the main consumer, switched to LEDs, demand and prices plummeted for a while, leading producers to reduce production.

Krypton is generally produced by concentrating oxygen in an ASU with a capacity of more than 50,000㎥ per hour, but this is because there is a risk of explosion and the profitability has been low due to the decline in krypton prices.

This led to a continuous decline in the price of krypton from 2010 to 2017.

Meanwhile, as usage in semiconductor 3D NAND has rapidly increased since 2017, the price of krypton has also risen.

3D NAND is a circuitry that stacks dozens of layers of planar (2D) NAND, and requires an etching process to drill holes to create channels that connect each layer.

At this time, Xe and Kr are used as auxiliary propulsion gases (Momentum Gas) to inject etching gas into deep holes.

Toshiba Memory of Japan (now Kioxia) is known to have first developed this method, initially using Xe but giving up because it was too expensive, then using Ar, and recently replacing it with Kr.

Companies currently using Krypton include SK Hynix, Kioxia, and Micron.

These companies are not stacking high-density 3D NAND at once.It is taking the approach of stacking two stacks like assembling NIN blocks. For example, the 96-layer 3D NAND commercialized by SK Hynix is two 48-layer 3D NANDs stacked.

Krypton, which is cheaper than xenon, is mainly used for etching 48-layer 3D NAND, but to produce 96 layers, twice as much krypton is needed as before.

Micron's 176-layer 3D NAND, announced in the second half of 2020, also uses 88-layer double stacking technology.

This is how krypton began to be used for semiconductor NAND, and it is known that more than 76% of the world's krypton is used for semiconductors.

Accordingly, as NAND production increases, demand for krypton is also rapidly increasing, and its price is also rising.

In particular, the production of krypton is limited, but demand continues to increase, so prices are expected to rise. Accordingly, the burden of krypton prices on the proportion of NAND production costs is expected to continue to increase.

In addition, Krypton distributors are spending more than in the past to secure inventory, making them more sensitive to the NAND flash market outlook as more accurate demand forecasts become necessary.

Domestic krypton distributors include Linde Korea, SK Materials, Daedeok Gas, TEMC, and Puem.