MEMs oscillator sensitivity to helium (helium kills iPhones)

TL;DR

Helium affects cell phones, causing strange failures within minutes, takes days to recover.

Transcript

today on Applied Science we're going to take a look at this interesting and bizarre failure mode of modern cell phones if you take a phone and put it in a plastic bag and then filled the bag up with helium in about ten minutes the phone will completely go dead and it will take three or four days for the phone to recover sounds completely ridiculous... Read More

Key Insights

• 🐢 Helium exposure affects cell phones, causing rapid malfunctions and slow recovery processes.
• 🔮 MEMS oscillators, replacing quartz crystals in devices, are highly sensitive to helium diffusion.
• 👻 Hermetically sealed devices allow for helium entry, resulting in fatal failures.
• 🎮 Helium diffusion process can be controlled through manufacturing techniques like HF etching.
• ☠️ Recovery time post-helium exposure is prolonged due to slow diffusion rates.
• 👷 Silicon construction of MEMS oscillators enables helium to penetrate the material, impacting the device's functionality.
• 🎨 Understanding helium diffusion in electronics is crucial for design and diagnostics in modern technology.

Questions & Answers

Q: How does helium affect cell phones?

When exposed to even small concentrations of helium, cell phones experience a rapid failure, causing the device to die within minutes. Recovery can take days due to helium diffusion.

Q: Why are MEMS oscillators susceptible to helium?

MEMS oscillators are made of pure silicon, allowing helium to diffuse through the material. This causes frequency changes and eventual crashes in the device.

Q: How are MEMS oscillators constructed?

MEMS oscillators consist of separate silicon dies—one for circuitry and one for the MEMS structure, sealed in silicon. They are hermetically sealed with small vents for HF etching.

Q: Why does it take days for devices to recover from helium exposure?

Helium diffusion in devices is slow, taking days for the gas to escape even in vacuum conditions. Recovery time is prolonged due to the nature of helium diffusion.

Summary & Key Takeaways

• Helium exposure kills cell phones within minutes but takes days to recover.

• MEMS oscillators replace quartz crystals in phones, sensitive to helium due to their tiny size.

• Devices can be sealed with silicon, allowing helium diffusion and causing failures.