The Recessed Trapezoidal Groove Dual‐Gate AlGaN/GaN E‐Mode Transistor by Using Depletion Enhancement Effect.

The recessed trapezoidal groove dual‐gate profile is achieved by the low power CF₄ plasma etching based on the principle of ion‐scattering. The recessed trapezoidal groove dual‐gate architecture can increase the lateral broadening of depletion width, yielding the Enhancement‐mode operation. This device demonstrates a threshold voltage of 0.43 V, a maximum drain current of 480 mA mm⁻¹ and a trans‐conductance of 308 mS mm⁻¹. The device exhibits a low off‐state leakage current of ≈10⁻¹⁰ A mm⁻¹ and gate induced drain leakage is effectively improved. An extrinsic current gain cut off frequency of 32 GHz and a maximum oscillation frequency of 65 GHz are deduced. The threshold voltage (V_th) stability of the Schottky gate HEMT is investigated. The recessed trapezoidal groove dual‐gate exhibits a small shift of V_th, which is attributed to the lateral extension of depletion region in the trapezoidal groove dual‐gate structure. [ABSTRACT FROM AUTHOR]