Superjunction has arguably been the most creative and important concept in the power device field since the introduction of the insulated gate bipolar transistor (IGBT) in the 1980s. It is the only concept known today that has challenged and ultimately proved wrong the well-known theoretical study on the limit of silicon in high-voltage devices. This paper deals with the history, device and process development, and the future prospects of Superjunction technologies. It covers fundamental physics, technological challenges as well as aspects of design and modeling of unipolar devices, such as CoolMOS. The superjunction concept is compared to other methods of enhancing the conductivity of power devices (from bipolar to employment of wide-bandgap materials) to derive its set of benefits and limitations. This paper closes with the application of the superjunction concept to other structures or materials, such as terminations, superjunction IGBTs, or silicon carbide Field Effect Transistors (FETs).

Superjunction Power Devices, History, Development, and Future Prospects

The present disclosure describes a methodology for wireless power transmission based on pocket-forming. This methodology may include one transmitter and at least one or more receivers, being the transmitter the source of energy and the receiver the device that is desired to charge or power. The transmitter may identify and locate the device to which the receiver is connected and thereafter aim pockets of energy to the device in order to power it. Pockets of energy may be generated through constructive and destructive interferences, which may create null-spaces and spots of pockets of energy ranged into one or more radii from transmitter. Such feature may enable wireless power transmission through a selective range, which may limit operation area of electronic devices and/or may avoid formation of pockets of energy near and/or over certain areas, objects and people.

Wireless power transmission with selective range

Configurations and methods of wireless power transmission for charging or powering one or more electronic devices inside a vehicle are disclosed. A transmitter capable of single or multiple pocket-forming may be connected to a car lighter, where this transmitter may include a circuitry module and an antenna array integrated within the transmitter, or operatively connected through a cable. This cable may allow the positioning of the antenna array in different locations inside the vehicle suitable for directing RF waves or pockets of energy towards one or more electronic devices. Transmitter's configuration can be accessed by one or more electronic devices through Bluetooth communication in order to set up charging or powering priorities.

Wireless charging and powering of electronic devices in a vehicle

The present disclosure may provide a wireless power system which may be used to provide wireless power transmission (WPT) while using suitable WPT techniques such as pocket-forming. Wireless power system may be used in a wireless powered house for providing power and charge to a plurality of mobile and non-mobile devices. Wireless powered house may include a single base station which may be connected to several transmitters. Base station may manage operation of every transmitter in an independently manner or may operate them as a single transmitter. Connection between base station and transmitters may be achieved through a plurality of techniques including wired connections and wireless connections.

Wireless powered house

Embodiments directed to providing health safety in a wireless power transmission systems are disclosed herein. One embodiment includes a processing apparatus with a processor; a data storage; and one or more wireless power transmitters each including at least two antennas. The one or more wireless power transmitters receive instructions from the processing apparatus that cause the transmitters to transmit RF waves that constructively interfere to provide wirelessly delivered power to one or more receivers. The processing apparatus receives and processes wireless power proscribing data for each respective receiver, respective wireless power proscribing data including at least one user-specified circumstance that a user inputs as to when a respective electronic device coupled with the respective receiver is in use; and the processing apparatus causes transmission of the RF waves by the transmitters in accordance with determining that the at least one user-specified circumstance is not present at the respective electronic device.

System and method for providing health safety in a wireless power transmission system

The tridimensional channel SOI-LIGBT on 1.5μm thin SOI layer is developed in this paper. The key feature of the device is that there are numerous separated P-body cells located in the emitter region, which can increase the efficient channel width, enhance electron injection and attain a large current capability. The proposed SOI-LIGBT exhibits the current density of 150A/cm2, which has an improvement of 150% compared with the conventional structure. The SOI-LIGBT structure can be well applied in high voltage integrated circuit (HVIC).

700V thin SOI-LIGBT with high current capability

In The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. In this paper, a high-switching-frequency single-switched quasi-resonant flyback converter that features low switching loss and low switching noise is proposed. A resonant inductor of primary side and a resonant capacitor of secondary side are utilized to recycle the transformer leakage energy and realize zero-current-switching (ZCS) at turn-off and valley-switching (VS) at turn-on of the primary switch, and ZCS turn-off of diode. The VS is realized based on the resonance between the resonant inductor and the equivalent switch drain capacitor which helps to realize near fully soft switching. Compared to traditional quasi-resonant converters, the switching loss is greatly reduced. And low cost, low losses and low switching noise are all acquired. The proposed concept has been validated on a 1MHz 12V/3A prototype with 80V dc input. The peak efficiency is 90.4% using GaN device without synchronous rectification in the open loop test.

A single-switched high-switching-frequency quasi-resonant flyback converter with zero-current-switching and valley-switching

A novel high-voltage interconnection (HVI) structure with dual trenches for 500V SOI-LIGBT is proposed in this paper. Compared with the conventional dual trenches structure, the proposed structure features a shallow trench (T1) and a deep trench (T2) beneath the HVI. By employing the shallow trench (T1), the potential can easily penetrate into the deep trench (T2) and the total potential sustained by the dual trenches (T1 and T2) is increased. The experimental results demonstrate that the proposed dual trenches structure can fully shield the influence of HVI with significant reduction in the area of the HVI region. With almost the same breakdown voltage of 550V as the conventional dual trenches structure, the length of the silicon region between the active region and the dual trenches in the proposed structure is shortened from 45um to 15um. The area of the HVI region is shrunk by 57% in comparison to the conventional dual trenches structure.

A novel high-voltage interconnection structure with dual trenches for 500V SOI-LIGBT

A novel 500-V rated silicon-on-insulator lateral insulated-gate bipolar transistor (SOI-LIGBT), featuring a W-shaped n-typed buffer and p-typed composite collectors, is proposed for the first time in this paper. The composite collectors which consist of a high-doped p+ layer and a low-doped p− layer can maintain a high level of collector-side hole injection in ON-state; the low-doped p− layer combining with the W-shaped buffer provides a low barrier path for electron extraction during turn-off; thus, high current capability and high turn-off speed can be realized at the same time. The measurement results show that 67.3% decrease in turn-off time can be obtained at the expense of only 6.3% of current capability. Compared with the standard SOI-LIGBT, no additional processing steps or process modifications are required for the proposed SOI-LIGBT. The low-doped p− collector is formed simultaneously with the emitter-side p-well while the W-shaped buffer is formed by diffusion overlapping of two neighboring windows. At 125 °C, the proposed SOI-LIGBT exhibits an ON-state voltage drop of 2.48 V, a saturated current density of 420 A/cm2, a turn-off time of $>4~\mu \text{s}$ , allowing significant improvements in power loss, operating frequency, and ruggedness for single-chip intelligent power ICs.

500-V Silicon-On-Insulator Lateral IGBT With W-Shaped n-Typed Buffer and Composite p-Typed Collectors

This work provides a physical insight into the failure of Superjunction MOSFET (SJ-MOSFET) for full bridge inverter system during an reverse recovery behavior. The inspection of failed SJ-MOSFET reveals burnt-out points in the vicinity of the device edge termination. To explore this result, physical TCAD simulations have been carried out. It is found that there is an extremely inhomogeneous reverse recovery behavior between the active region and the termination region in the SJ-MOSFET. And a destructive dynamic avalanche phenomenon is occurred at the edge of the termination, which is identified as responsible for the observed failure. Finally, an optimization termination structure with P+ dynamical field limiting ring (DFLR) is proposed to suppress the dynamical avalanche and the reverse recovery robustness of the proposed structure is improved by 200%.

Jing Zhu

Papers

700V thin SOI-LIGBT with high current capability

A single-switched high-switching-frequency quasi-resonant flyback converter with zero-current-switching and valley-switching

A novel high-voltage interconnection structure with dual trenches for 500V SOI-LIGBT

500-V Silicon-On-Insulator Lateral IGBT With W-Shaped n-Typed Buffer and Composite p-Typed Collectors

Investigations of inhomogeneous reverse recovery behavior of the body diode in superjunction MOSFET