Atomic layer deposited (ALD) high-dielectric-constant (high-k) materials have found extensive applications in a variety of electronic, optical, optoelectronic, and photovoltaic devices. While electrical, optical, and interfacial properties have been the primary consideration for such devices, thermal and mechanical properties are becoming an additional key consideration for many new and emerging applications of ALD high-k materials in electromechanical, energy storage, and organic light emitting diode devices. Unfortunately, a clear correspondence between thermal/mechanical and electrical/optical properties in ALD high-k materials has yet to be established, and a detailed comparison to conventional silicon-based dielectrics to facilitate optimal material selection is also lacking. In this regard, we have conducted a comprehensive investigation and review of the thermal, mechanical, electrical, optical, and structural properties for a series of prevalent and emerging ALD high-k materials including aluminum oxide (Al 2 O 3 ), aluminum nitride (AlN), hafnium oxide (HfO 2 ), and beryllium oxide (BeO). For comparison, more established silicon-based dielectrics were also examined, including thermally grown silicon dioxide (SiO 2 ) and plasma-enhanced chemically vapor deposited hydrogenated silicon nitride (SiN:H). We find that in addition to exhibiting high values of dielectric permittivity and electrical resistance that exceed those of SiO 2 and SiN:H, the ALD high-k materials exhibit equally exceptional thermal and mechanical properties with coefficients of thermal expansion ≤ 6 × 10 -6 / • C, thermal conductivites (κ) of 3-15 W/m K, and Young's modulus and hardness values exceeding 200 and 25 GPa, respectively. In many cases, the observed extreme thermal/mechanical properties correlate with the presence of crystallinity in the ALD high-k films. In contrast, some of the electrical and optical properties correlate more strongly with the percentage of ionic vs. covalent bonds present in the high-k film. Overall, the ALD high-k dielectrics investigated concurrently exhibit compelling thermal/mechanical and electrical/optical properties. The drive to reduce gate leakage currents in highly scaled complementary metal-oxide-semiconductor (CMOS) transistors has led to the exploration and development of a wide variety of high-dielectricconstant (high-k) materials to replace silicon dioxide (SiO 2 ) as the insulating gate dielectric material.1-8 Many of these same high-k materials have found additional applications in future non-CMOS logic and memory storage products such as solid-state electrolytes in resistive switching devices, 9,10 tunnel barriers in spin-transport devices, 11 and as a ferroelectric in magnetoelectric devices. While electrical, physical, and thermodynamic properties have clearly been a key consideration in all of the above applications, thermal properties have become an additional important consideration for higk-k dielectrics as aggressive dimensional scaling of devices has created the need to dissipate ...

We investigate the structural and quantum transport properties of isotopically enriched 28 Si/ 28 SiO 2 stacks deposited on 300-mm Si wafers in an industrial CMOS fab. Highly uniform films are obtained with an isotopic purity greater than 99.92%. Hall-bar transistors with an oxide stack comprising 10 nm of 28 SiO 2 and 17 nm of Al 2 O 3 (equivalent oxide thickness of 17 nm) are fabricated in an academic cleanroom. A critical density for conduction of 1.75 × 10 11 cm −2 and a peak mobility of 9800 cm 2 /Vs are measured at a temperature of 1.7 K. The 28 Si/ 28 SiO 2 interface is characterized by a roughness of = 0.4 nm and a correlation length of = 3.4 nm. An upper bound for valley splitting energy of 480 μeV is estimated at an effective electric field of 9.5 MV/m. These results support the use of wafer-scale 28 Si/ 28 SiO 2 as a promising material platform to manufacture industrial spin qubits.

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To enable the continued scaling of integrated circuits, the semiconductor industry faces ongoing struggles to implement better low‐dielectric‐constant (low‐k) materials within the interconnect system. One of the biggest challenges to integrating new dielectrics is overcoming the low‐k death curve—that is, the fatal falloff in mechanical properties associated with the low material densities required to achieve low k values. It is shown that amorphous hydrogenated boron carbide (a‐BC:H) films exhibit Young's modulus (E) values between two and ten times greater than those of state‐of‐the‐art Si‐based dielectric materials across a wide range of k values. In particular, optimized a‐BC:H films with moderate k values in the range of 3–4, in addition to possessing outstanding stiffness (E ≈ 100–150 GPa), simultaneously exhibit excellent electrical properties (leakage current of <10–8 A cm–2 at 2 MV cm–1 and breakdown voltage of >5 MV cm–1). Films in this range also demonstrate resistance to Cu diffusion to at least 600 °C, as well as chemical stability and etch properties suitable for low‐k diffusion barrier/etch stop applications.

Boron carbon nitride (BCN) thin films were deposited by a dual target DC and RF sputtering technique. The films were deposited using various combinations of nitrogen and argon working gases and B 4 C, BN, and C targets. X-ray photoelectron spectroscopy and Fourier-transform infra-red spectroscopy were utilized, respectively, to investigate the changes in chemical composition and bonding that occurred for films deposited under various N 2 /Ar gas flow ratios and DC/RF target powers. The composition and bonding were correlated to separate measurements of the BCN mass density, dielectric constant, Young's modulus, and hardness. All BCN films were observed to have relatively low mass densities ranging from 2.0-2.5 g/cm 3 . BN rich BCN films were observed to be insulating with relatively low dielectric constants of 3.9-4.6 and Young's modulus and hardness values of 110-150 GPa and 5-13 GPa, respectively. BC rich BCN films were observed to be comparatively leaky dielectrics but did exhibit extreme mechanical properties with Young's modulus and hardness values exceeding in some cases 300 GPa and 30 GPa, respectively. Nanoelectronic metal interconnects have many unique nanoscale electrical, thermal, and mechanical challenges.1-3 While dimensional scaling has produced tremendous improvements in transistor performance, 4 it has produced an opposite effect on the associated metal interconnect leading to increased critical path signal delays and possible degradation of the overall integrated circuit performance.5 As the interconnect signal delays are proportional both to the resistance of the interconnect metal and the capacitance of the insulating interlayer dielectric (ILD), new materials with reduced values of resistivity and dielectric permittivity have been sought to mitigate the negative effects of dimensional scaling.5 Since relatively few materials exhibit a lower resistivity compared to the currently utilized interconnect metal copper (Cu), most materials based interconnect delay reduction efforts have focused on implementing new ILD materials with increasingly lower values of dielectric constant (i.e. low-k).6 Unfortunately, the hybrid inorganic-organic silicate (a-SiOC:H) materials currently utilized as low-k ILDs exhibit reduced electrical, thermal and mechanical properties in addition to reduced values of dielectric permittivity.5-7 These overall reduced properties have severely aggravated a variety of interconnect related reliability issues such as time dependent dielectric breakdown and die cracking during packaging. 2,3Compounds in the boron-carbon-nitrogen phase diagram (such as diamond (C), cubic boron nitride (c-BN), and boron carbide (B 4 C)) are potentially attractive as alternative low-k dielectric materials due to their covalent bonding, short bond lengths, and low atomic mass that leads to a unique combination of low dielectric constant but high thermal and mechanical strength. [8][9][10][11][12] Some of the already prominently reported properties for these materials include good wear resistance, hig...