Proposed TeraHertz transistor using a compliant universal substrate

A TeraHertz transistor becomes feasible by using a twist-bonded Compliant Universal (CU) substrate with stress compensation in a modulation doped field effect transistor. A GaAs twist-bonded CU-substrate with an effective lattice constant of 5.95 Å, allows a 100 Å compressively strained InAs quantum well to be epitaxial grown between two tensilely strained layers of Al_0.55In_0.45As without exceeding the overall critical layer thickness. By confining the two dimensional electron gas to the pseudomorphic InAs quantum well with proper design techniques the alloy scattering will be eliminated and the carriers will be limited to only n=1 states with room temperature low field mobilities of >25,000 cm²/V-sec. By using a simple analytical model for a double-doped double-strained modulation doped field effect transistor two dimensional electron gas densities of >3.5×10¹² cm^-2 are predicted. These values will ensue a channel resistance of <70 Ω/square, an effective carrier velocity of >4×10⁷ cm/sec and with a sub-0.1 μm gate a frequency response greater than a TeraHertz