A metamorphic heterostructure field-effect transistor with a double delta-doped channel
This study presents a metamorphic heterostructure field-effect transistor with a double δ-doped channel (MDDFET). The coupled δ-doped In0.5Ga0.5As/δ+/In0.5Ga0.5As/In0.6Ga0.4As/In0.5Ga0.5As/δ+/In0.5Ga0.5As channel demonstrates high carrier concentration and high mobility due to the good carrier confinement of the δ-doped design and the coupled wavefunction in the undoped In-rich channel. Experimental results indicate that the MDDFET with the gate dimension of 0.65 × 100 µm2 exhibits a maximum extrinsic transconductance of 320 mS mm−1, a saturated drain current density of 566 mA mm−1 at VGS = 0 V, a cut-off frequency of 45 GHz, a maximum oscillation frequency of 125 GHz and a saturated power of 15.9 dBm at 5.8 GHz. These results demonstrate that this studied device is appropriate for high-frequency and high-power applications.