Comprehensive study of thermal stability performance of metamorphic heterostructure field-effect transistors with TiAu and Au metal gates

The thermal stability performance of double δ -doped In0.42 Al0.58 As In0.46 Ga0.54 As metamorphic heterostructure field-effect transistors with Au and TiAu metal gates are comprehensively studied and demonstrated. By evaporating the TiAu metal gate, the thermal stability of device characteristics are significantly improved as compared with the device with conventional metal gate (Au). Experimentally, the device with a TiAu metal gate simultaneously exhibits the considerably lower temperature degradation in turn-on voltage (-2.19 mVK), breakdown voltage (-34 mVK), logic swing (-1.24 mVK), transition region width (0.05 mVK), on-off current ratio (-3.55 K), threshold voltage (-0.25 mVK), impact ionization-induced gate current (1.63× 10-3 μAmm K), output conductance (1.23 μSmm K), and voltage gain (-0.33 K) as the temperature is increased from 300 to 510 K. Consequently, the studied device with a TiAu metal gate is a good candidate for high-speed and high-temperature digital and switching circuit applications.