Development of high-k dielectric for antimonides and a sub 350°C III–V pMOSFET outperforming Germanium

In_xGa_1-xSb channel materials have the highest hole and electron mobility among all III-V semiconductors, high conduction and valence band offsets (CBO/VBO) with lattice matched Al_xIn_1-xSb for heterostructure MOSFET design and allow low thermal budget MOSFET fabrication (Figure 1). While buried channel HEMT-like devices with excellent electron and hole transport have been demonstrated, realization of an Sb-channel MOSFET has remained elusive due to the highly reactive nature of the Sb-surface (Figure 2). In this paper we overcome these challenges (Figure 1) and fabricate an In_xGa_1-xSb pMOSFET with high hole mobility (μ_b) : a bottleneck for III-V complimentary logic. Synchrotron Radiation Photoemission Spectroscopy (SRPES) is used to aid the development of ALD AI₂O₃ on GaSb with a mid bandgap Dit of 3 x 10¹¹/cm²V^-1. A p⁺/n diode with ideality factor of 1.4 and I_ON/I_OFF >; 5 x 10⁴ is developed. pMOSFETs with various channel configurations to optimize the hole transport are fabricated using a sub 350°C gate-first process. Surface (buried) channel pMOSFETs with peak μ_h of 620 (910) cm²/Vs and having more than 50 (100) % higher mobility than Germanium over the entire sheet charge (N_s) range are demonstrated and analyzed.