Logic

The integration of III-V semiconductors on silicon (Si) substrate has been an active field of research for more than 30 years. Various approaches have been investigated, including growth of buffer layers to accommodate the lattice mismatch between the Si substrate and the III-V layer, Si- or Ge-on-insulator, epitaxial transfer methods, epitaxial lateral overgrowth, aspect-ratio-trapping techniques, and interfacial misfit array formation. However, manufacturing standards have not been met and significant levels of remaining defectivity, high cost, and complex integration schemes have hampered large scale commercial impact. Here we report on low cost, relaxed, atomically smooth, and surface undulation free lattice mismatched III-V epitaxial films grown in wide-fields of micrometer size on 300 mm Si(100) and (111) substrates. The crystallographic quality of the epitaxial film beyond a few atomic layers from the Si substrate is accomplished by formation of an interfacial misfit array. This development may enable future platforms of integrated low-power logic, power amplifiers, voltage controllers, and optoelectronics components.

In 0.53 Ga 0.47 As FinFETs are fabricated on 300 mm Si substrate. High device performance with good uniformity across the wafer are demonstrated (SS=78 mV/dec., I on /I off ~10 5 , DIBL=48 mV/V, g m =1510 μS/μm, and I on =301 μA/μm at V ds =0.5V with L g =120 nm device). The extrinsic field effect mobility of 1731 cm 2 /V-s with EOT~0.9nm is extracted by split-CV. Devices fabricated on 300mm Si have shown similar performances in SS and I on when benchmarked with device fabricated on lattice-matched InP substrate. In addition, an I on of 44.1 μA per fin is observed on the fin-height of 70 nm and the fin-width of 25nm, which is among the highest values reported for In 0.53 Ga 0.47 As FinFETs to the best of our knowledge.

InAs nanowires (NW) grown by MOCVD with diameter d as small as 10 nm and gate-all-around (GAA) MOSFETs with d = 12-15 nm are demonstrated. I on = 314 μA/μm, and S sat =68 mV/dec was achieved at V dd = 0.5 V (I off = 0.1 μA/μm). Highest g m measured is 2693 μS/μm. Device performance is enabled by small diameter and optimized high-k/InAs gate stack process. Device performance tradeoffs between g m , R on , and I min are discussed.

We report the first demonstration of InAs FinFETs with fin width W fin in the range 25-35 nm, formed by inductively coupled plasma etching. The channel comprises defect-free, lattice-matched InAs with fin height H fin = 20 nm controlled by the use of an etch stop layer incorporated into the device heterostructure. For a gate length L g = 1 μm, peak transconductance gm,peak = 1430 μS/μm is measured at V d = 0.5 V demonstrating that electron transport in InAs fins can match planar devices.

We report an in-depth atomistic study of the scaling potential of III-V GAA nanowire heterojunction TFET using an innovative tight-binding mode space (MS) technique with large speedup (up to 250×) while keeping good accuracy (error <; 1%). It is shown that both n- and pTFET performances are best above 20 nm gate length for a cross-section of 5.5 nm in the [111] crystal orientation. At V dd = 0.3 V and I off = 50 pA/μm, the on-current (Ion) and energy-delay product (ETP) gain over a Si NW GAA MOSFET are 58× and 56× respectively. In a beyond 5 nm node low power ITRS 2.0 horizontal GAA design rule however, where the gate length is restricted to 12 nm, a [100] orientation is best but features up to 3× I on and 2.4× ETP degradation vs. the 20 nm TFET GAA design.

We report on the first realization of InAs n-channel gate-all-around nanowire MOSFETs on 300 mm Si substrates using a fully very large-scale integration (VLSI)-compatible flow. Scaling of the equivalent oxide thickness EOT in conjunction with high-κ dielectric engineering improves the device performance; with an optimized gate stack having an EOT of 1.0 nm, the sub-threshold swing S is 76.8 mV/dec., and the peak transconductance gm is 1.65 mS/μm, at V ds of 0.5 V, for a gate-all-around nanowire MOSFET having a gate length L g of 90 nm, a nanowire height H NW of 25 nm, and a nanowire width W NW of 20 nm, resulting in Q ≡ gm/S = 21.5, a record for InAs on silicon. Furthermore, we report a source/drain resistance R sd of 160-200 Ω·μm, amongst the lowest values reported for III-V MOSFETs. Our VLSI-compatible process provides high device yield, which enables statistically reliable extraction of electron transport parameters, such as unidirectional thermal velocity vtx of 3-4×10 7 cm/s and back-scattering coefficient r c as a function of gate length.

This work investigates the formation mechanism of stress memorization technique (SMT)-induced edge dislocations and stacking faults during solid-phase epitaxy regrowth (SPER) using molecular dynamics (MD) simulation. During the SPER process of a patterned amorphous Si under a high-tensile capping film, growth fronts along the (1 1 0) and (0 0 1) planes collapse to form 5- and 7-rings which trigger the Frankel partial dislocation in the {1 1 1} plane. In addition, the line defects of stacking faults along {1 1 1} plane are generated with two symmetric boundaries of atomic structures which are confirmed as micro-twin defects. The MD simulation results are validated using high-resolution transmission electron microscopy and inverse fast Fourier transform images. The strain distribution obtained from the atomic structure reveals that the stress field is mainly caused by Frankel partial dislocations and the minor stress effect from the micro-twin defects.

This work highlights the impact of SMT-induced edge-dislocation positions in nFET device design. Based on experimental results and atomic transport simulation, dislocations with reduced proximity and depth would increase the amount of SFs and TDs which induce high parasitic resistance and high I boff leakage current together. Trade-off among strained mobility, parasitic resistance and I boff should be made for advanced device design.

In 0.53 Ga 0.47 As channel MOSFETs were fabricated on 300 mm Si substrate. The epitaxial In 0.53 Ga 0.47 As channel layer exhibits high Hall electron mobility comparable to those grown on lattice matched InP substrates. Excellent device characteristics (SS~95 mV/dec., I on /I off ~10 5 , DIBL ~51 mV/V at V ds = 0.5V for L g =150 nm device) with good uniformity across the wafer were demonstrated. The extracted high field effect mobility (μ EF = 1837 cm 2 /V-s with EOT ~ 0.9 nm) is among the highest values reported for surface channel In 0.53 Ga 0.47 As MOSFETs.

High mobility channel materials could replace strained Si to enhance speed performance and/or reduce power consumption in future transistors. Ge has the highest hole mobility among common elemental and compound semiconductors, and an electron mobility that is two times larger than that of Si. Ge is thus a promising channel material for future CMOS (Fig. 1). Key challenges include cost-effective integration of Ge on Si in a manufacturable process, formation of high-quality gate stack on Ge for n- and p-FETs at aggressively scaled EOTs that deliver high channel mobilities, and leakage issues related to its small bandgap. In this paper, we discuss recent research progress in advancing Ge-based transistor technologies. Integration of Ge on Si substrate to enable fabrication of high performance devices and formation of high-quality gate stack for Ge FETs (particularly for n-FETs) will be discussed. We also explore opportunities to boost the mobility of Ge, e.g. by incorporating Sn in Ge to form Ge 1-x Sn x . Furthermore, by raising the Sn composition, the band gap E G of Ge 1-x Sn x becomes smaller and transits from indirect to direct, making Ge 1-x Sn x a promising material for tunneling transistors.