RF and Logic Performance Improvement of In0.7Ga0.3As/InAs/In0.7Ga0.3As Composite-Channel HEMT Using Gate-Sinking Technology

摘要

Eighty-nanometer-gate $hbox{In}_{0.7}hbox{Ga}_{0.3}hbox{As}/hbox{InAs}/ hbox{In}_{0.7}hbox{Ga}_{0.3}hbox{As}$ composite-channel high-electron mobility transistors (HEMTs), which are fabricated using platinum buried gate as the Schottky contact metal, were evaluated for RF and logic application. After gate sinking at 250 $^{circ}hbox{C}$ for 3 min, the device exhibited a high $g_{m}$ value of 1590 mS/mm at $V_{d} = hbox{0.5} hbox{V}$, the current-gain cutoff frequency $f_{T}$ was increased from 390 to 494 GHz, and the gate-delay time was decreased from 0.83 to 0.78 ps at supply voltage of 0.6 V. This is the highest $f_{T}$ achieved for 80-nm-gate-length HEMT devices. These superior performances are attributed to the reduction of distance between gate and channel and the reduction of parasitic gate capacitances during the gate-sinking process. Moreover, such superior performances were achieved through a very simple and straightforward fabrication process with optimal epistructure of the device.