4 ms·

Whats the hold up with Gallium-Arsenid (instead of silicon)? The PN junction threshold is 0.3V (instead of 0.7V for silicon). This would disipate less heat tha

• ryacko 8y ago
  Likely the typical material sciences reasons, having to do with heat, strength, expansion, etc.
  • Scipio_Afri 8y ago
    From my experience, its really brittle.
• BostonEnginerd 8y ago
  We’ve been working with GaAs for a long time. You likely have a fair bit of it in your phone. A few things prevent its use for advanced CMOS - base material quality is inferior to Si, it’s not available in 12” substrates, and the cost is high. You will likely see material integration of III-V material systems into Si, rather than using standalone GaAs for logic.
• deepnotderp 8y ago
  1. As we move to lower nodes, high carrier mobility materials such as GaAs actually perform worse than silicon due to increased source/drain direct tunneling. See: https://ieeexplore.ieee.org/document/7479214 https://ieeexplore.ieee.org/document/7479214 2. Most III-V materials have excellent electron mobility, making for great n-type transistors, but tend to have poor hole mobility which means bad p-type transistors. Germanium has high hole mobility, and it is already used in very small quantities to boost performance (see "germanium stressors") 3. Most III-Vs have no native oxide, nowadays at 28nm onwards due to the use of high-k dielectrics. However: Until recently, the growth of oxides on III-V materials without defects such as fermi level pinning was a Hard Problem.
  • BostonEnginerd 8y ago
    That’s a great reference!