| 摘要 |
PURPOSE:To form a logic circuit having large noise margin by forming a nitride film directly of a nitride on the active layer of a GaAs substrate, and forming a gate electrode thereon. CONSTITUTION:A photoresist 2 is patterned on a semiinsulating GaAs substrate 1, and Si ions are implanted to selectively form an n-type active layer 3. After this ion implantation, it is, for example, heat-treated at 800 deg.C for 15 min. in an AsH3/Ar atmosphere to activate the impurity. Thereafter, a substrate from which the photoresist 2 is removed is placed in a plasma chamber, and plasma process (N2 plasma process) is conducted for 30 min in a discharge nitrogen. Thus, a nitride film (GaN) 4 having approx. 40Angstrom of thickness is formed on the surface. Then, a WNX is deposited by reactive sputtering, and patterned to form a high melting point metal gate electrode 5. Thus, a quasi-MIS structure having high barrier is provided, mutual conductance is increased, and its stability can be improved. |
