In₀.₅₃Ga₀.₄₇As/InAs Composite Channel MOS-HEMT Exhibiting 511 GHz fτ and 256 GHz f max

Abstract

An In 0.53 Ga 0.47 As/InAs composite channel MOS-HEMT exhibiting peak $f_{\tau } = 511$ GHz and peak ${f} _{\max }= 285$ GHz is demonstrated. Additionally, another device exhibiting peak $f_{\tau } = 286$ GHz and peak ${f} _{\max }= 460$ GHz is reported. The devices have a 1 nm / 3 nm Al x O y N z interfacial layer and ZrO 2 gate dielectric on a 2 nm / 4 nm In 0.53 Ga 0.47 As / InAs composite channel with a modulation doped In 0.52 Al 0.48 As back barrier. To reduce parasitic gate-source and gate-drain capacitances, a modulation doped In 0.52 Al 0.48 As / In 0.53 Ga 0.47 As / InAs composite quantum well is included between the gate edges and the N+ source and drain. Compared to the work of Wu et al. , addition of an In 0.52 Al 0.48 As back-barrier, scaling of S/D metal spacing, and scaling of channel thickness has enabled improved transconductance and increased ${f} _{\tau }$ . Short gate length devices ${f} _{\max }$ are limit by high $R_{G}$ due to poor metal filling of the T-Gate stem and large $C_{DS}$ due to a conductive etch stop layer. Long gate length devices exhibit better metal filling, reduced $R_{G}$ , and balanced ${f} _{\tau }$ , ${f} _{\max }$ . Devices exhibit 10–15% DC-1 GHz $g_{m,e}$ suggesting that the high-k / semiconductor interface has low $D_{it}$ .