Title :
Interfacial gate resistance in Schottky-barrier-gate field-effect transistors
Author :
Rohdin, Hans ; Moll, Nick ; Su, Chung-yi ; Lee, Gregory S.
Author_Institution :
Hewlett-Packard Co., Palo Alto, CA, USA
fDate :
12/1/1998 12:00:00 AM
Abstract :
We discuss in depth a previously overlooked component in the gate resistance Rg of Schottky-Barrier-Gate FETs, in particular, 0.1-μm gate-length AlInAs/GaInAs MODFETs. The high-frequency noise and power gain of these FETs depend critically on Rg. This has been the motivation for the development of T-gates that keep the gate finger metallization resistance Rga (proportional to the gate width Wg) low, even for very short gate length Lg . Rga increases with frequency due to the skin effect, but our three-dimensional (3-D) numerical modeling shows conclusively that this effect is negligible. We show that the always “larger-than-expected” Rg is instead caused by a component Rgi that scales inversely with Wg. We interpret Rgi as a metal-semiconductor interfacial gate resistance. The dominance of Rgi profoundly affects device optimization and model scaling. For GaAs and InP-based SBGFETs, there appears to exist a smallest practically achievable normalized interfacial gate resistance rgi on the order of 10-7 Ω cm2
Keywords :
III-V semiconductors; Schottky gate field effect transistors; aluminium compounds; gallium arsenide; high electron mobility transistors; indium compounds; semiconductor device metallisation; semiconductor device models; skin effect; 0.1 micron; AlInAs-GaInAs; AlInAs/GaInAs MODFET; SBGFET; Schottky barrier gate field effect transistor; T-gate; device optimization; gate finger metallization; high frequency noise; metal-semiconductor interfacial gate resistance; power gain; skin effect; three-dimensional numerical model; Equivalent circuits; Fingers; Frequency; HEMTs; MESFETs; MODFETs; Metallization; Numerical models; Schottky gate field effect transistors; Skin effect;
Journal_Title :
Electron Devices, IEEE Transactions on
