Device linear improvement using SiGe/Si heterostructure delta-doped-channel field-effect transistors

Results of boron delta-doped-channel (DDC) field-effect transistors fabricated on Si_0.7Ge_0.3/Si strained-layer heterostructures grown by solid-source molecular beam epitaxy (SSMBE) are reported. A device with a 1×100 μm² gate exhibits an extrinsic transconductance as high as 22 mS/mm. Due to the absence of parallel conduction effects under high-current-level operation in this device, as compared to a modulation-doped structure, a wide and flat range of uniform g_m distribution of 4.5 V together with a high gate-to-drain breakdown voltage (>25 V) and high current density of 120 mA/mm is obtained at room temperature, which is expected to provide an additional degree of freedom for Si-based device applications.