Ultrahigh-speed InP-based D- and E-mode MODFETs with ultra-shortelectrochemically-recessed gate contacts

摘要

Summary form only given. When the gate length L_g ofnmodulation-doped field-effect transistors (MODFETs) is reduced to deepnsub-0.1 μm range in pursuit of higher speed, it is most important tonsimultaneously reduce the gate-to-channel separation. The resulting highnaspect ratio alleviates both the reduction of transconductance g_mn resulting from drain-induced barrier lowering and the shift ofnthreshold voltage V_th. While the former point is essentialnfor ultrahigh-speed ICs, the latter is the key to implementingnenhancement-mode MODFETs (E-MODFET). However, the high aspect ratio isndifficult to attain due to the enlarged side etching of gate groovesnduring recess etching, which leads to higher parasitic resistance. Thenelectrochemical etching provides a feasible and easy-to-performntechnology to form deep and narrow gate grooves for ultrahigh-speednMODFETs