A possible scaling limit for enhancement-mode GaAs MESFETs in DCFL circuits

A possible scaling limit for ion-implanted GaAs MESFETs with buried p-layer LDD structure has been numerically investigated. A Schottky-contact model with a thin interfacial layer and interface states was used to simulate the Schottky-barrier height of a scaled-down MESFETs. When enhancement-mode MESFETs in direct-coupled FET logic (DCFL) circuits are scaled down, the gate length can be reduced to 0.21 mu m at an interface-state density of 6.6*10/sup 12/ cm/sup -2/.eV/sup -1/, when the barrier height is greater than 0.6 V, the threshold voltage is less than 0.1 V, and the channel aspect ratio is 8.<
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