Ohmic contacts to p-type In0.25Ga0.75Sb, InAs, and InAs0.8P0.2 have been investigated for the base of heterojunction bipolar transistors. On all these semiconductors, using Pd and/or Pt as the first layer in the metallization stack provided the lowest contact resistances. Specific contact resistances as low as 3 × 10-7 Ω-cm2 were measured for Au/W/Pd/p-InGaSb. Thin reactive layers of Pd or Pt were used beneath an unreactive W barrier to keep the contacts shallow, but contact resistance and thermal stability were sacrificed when 2 nm of Pd was used instead of 5 nm. The lowest contact resistance we measured on p-InAs was obtained with Pd/Pt/Au, but Pd/W/Au exhibited better thermal stability at 250°C. For p-type InAsP, Pd/Ru/Au provided a specific contact resistance of 4 × 10-6 Ω-cm2 as deposited. The contact consumed only 4 ± 2 nm of InAsP after 3 days at 250°C, and its resistance remained low. copyright The Electrochemical Society.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Dec 1 2006|
|Event||State-of-the-Art Program on Compound Semiconductors 45 (SOTAPOCS 45) -and- Wide Bandgap Semiconductor Materials and Devices 7 - 210th Electrochemical Society Meeting - Cancun, Mexico|
Duration: Oct 29 2006 → Nov 3 2006
All Science Journal Classification (ASJC) codes