To overcome the limitations of chemical doping in nanometer-scale semiconductor devices, electrostatic doping (ED) is emerging as a broadly investigated alternative to provide regions with a high electron or hole density in a semiconductor device. In this paper, we review various reported ED approaches and related device architectures in different material systems. We highlight the role of metal and semiconductor workfunctions, energy bandgap, and applied electric field and the interplay between them for the induced ED. The effect of interface traps on the induced charge is also addressed. In addition, we discuss the performance benefits of ED devices and the major roadblocks of these approaches for potential future CMOS technology.

Due to their superior material properties, wide bandgap (WBG) semiconductors enable the application of power electronics at higher temperature operation, higher frequencies, and higher efficiencies compared to silicon (Si). However, the commonly-used aluminum wire bonding as topside interconnection technology prevents WBG semiconductors from reaching their full potential, due to inherent parasitic inductances, large size, heat dissipation, and reliability issues of wire bonding technology. Therefore, this article presents a comprehensive review of topside interconnection technologies of WBG semiconductor power devices and modules. First, the challenges and driving factors for the interconnection of WBG semiconductor dies are discussed. Second, for each widely commercially used WBG semiconductor, i.e., silicon carbide and gallium nitride, technical details and innovative features of state-of-the-art interconnection techniques in packages are reviewed. Then, the majority of existing topside interconnection materials for WBG semiconductors are categorized and compared, followed by a discussion of their advantages, challenges, and failure modes. Based on this elaborate discussion, potential future directions of the interconnection technology development are given. It is concluded that the superior performance of WBG semiconductors can be obtained by combining novel materials with innovative designs for the topside interconnections.

This work presents the modeling of light emission from silicon based p⁺n junctions operating in avalanche breakdown. We revisit the photon emission process under the influence of relatively high electric fields in a reverse biased junction ($>{10}^5$ V/cm). The photon emission rate is described as a function of the electron temperature $T_{\mathrm{e}}$ , which is computed from the spatial distribution of the electric field. The light emission spectra lie around the visible spectral range ($\lambda \sim$ 300–850 nm), where the peak wavelength and the optical intensity are both doping level dependent. It is theoretically derived that a specific minimum geometrical width ($\sim 170$ nm) of the active region of avalanche is required, corresponding to a breakdown voltage of ∼5 V, below which the rate of photon emission in the desired spectrum drops. The derived model is validated using experimental data obtained from ultra-shallow p⁺n junctions with low absorption through a nm-thin p⁺ region and surface coverage of solely 3 nm of pure boron. We observe a peak in the emission spectra near 580 nm and 650 nm for diodes with breakdown voltages 7 V and 14 V, respectively, consistent with our model.

We report on a feature for the transistor, a piezoelectric layer to modulate the strain in the channel. The strain is proportional to the gate-source voltage, and thus increases as the device is turned on. As a result, the device has the leakage current of a relaxed device and the lower threshold voltage of a strained device. Our results, obtained by combining electrical and mechanical simulations, demonstrate that strain modulation can result in a 9 mV/decade smaller subthreshold swing for a FinFET.

Conventional packaging technologies cannot facilitate full utilization of wide bandgap (WBG) power modules due to the parasitics of wire bonds and the thermal stresses in solder layers. Pressure contact technology is considered to be an effective approach to reduce stress and to make the assembly compact by replacing solder materials and wire bonds. This article reviews the state of the art of pressure contact packaging and discusses the advantages and limitations of various adopted methodologies. The challenges are revealed in detail in terms of die metallization, multiphysical design, stress distribution, and failures in pressure-based joints. In addition, potential future trends of pressure contact packaging toward different power levels and strategies to select appropriate technologies for different scenarios are discussed. This work aims to support designers in implementing pressure contacts in WBG power modules to fully exploit their advantages and to improve the reliability in thermal cycling.

Avalanche-mode light-emitting diodes (AMLEDs) in silicon (Si) are potential light sources to enable monolithic optical links in standard CMOS technology, due to the large overlap of their electroluminescent (EL) spectra with the responsivity of Si photodiodes. These EL spectra depend on the reverse electric field. We present AMLEDs employing the superjunction (SJ) assisted reduced surface-field (RESURF) effect, which increases the uniformity of their electric field profile. Consequently, the EL area of these lateral devices is significantly enlarged as compared with conventional AMLEDs. Electrical and optical measurements demonstrate RESURF, as predicted by TCAD simulations, and show a direct link between EL-intensity (optical power per unit device area) and the field profile. Contrary to a conventional AMLED, the breakdown voltage of the avalanche-mode SJ-LED scales with the device length. Furthermore, the brightest SJ-LED, with a lateral intensity of ~30 mW cm ^-2 at an electrical power (PAMLED) of 0.1 W, shows a twofold higher internal quantum efficiency and a threefold higher EL-intensity compared with the conventional AMLED for the same PAMLED. This particular SJ-LED also shows an optimum radiative recombination efficiency at a current density of around ~800 A cm ^-2 .