The overall growing trend towards electrification and, at the same time, the urgent need to minimize energy consumption strongly requires higher energy efficiency in power electronics. We present a new technology concept for next generation 1200 V IGBTs with vastly reduced overall power losses using an optimized micro-pattern trench (MPT) cell design with sub-micron mesas. Further important parameters relevant for inverters driving electrical machines were optimized, including turn-off softness, dv/dt-controllability, and short circuit capability, providing a right-fit solution to customer requirements.

Proton implantation is one of many processes used to adjust the electronic and mechanical properties of silicon. Though the process has been extensively studied, it is still not clear which exact defects are formed and what their concentration profiles are. In this article, a simulation method is presented, which provides a better under-standing of the implantation process. The simulation takes into account the diffusion of mobile point defects and their reactions to defect complexes, as well as the dissociation of defect complexes. Concentration profiles for a set of defect complexes after an implantation at 400 keV and a dose of 5 x 10(14) H+ cm(-2) are presented. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

As in other semiconductor industries, there is a strong trend to use larger wafer diameters for the fabrication of power devices. However, for wafer diameters above 200 mm float-zone (FZ) silicon which is traditionally used for IGBTs is not available. Therefore, there is a need to use silicon material which has been fabricated by the magnetic Czochralski (Cz) method to make use of 300 mm wafers for IGBT-production. As this material contains a relatively high concentration of oxygen, the influence of carbon/oxygen-complexes has to be taken into account. CIOI-complexes can be decorated with hydrogen atoms resulting in donor-like complexes. Particularly, the application of proton-irradiation for the doping of the field-stop zone results in a relatively high concentration of interstitial carbon which is continuatively associated with the generation of undesired donors.

Hydrogen-related donors can be formed by using only a moderate thermal budget, so that this process can be used to create field-stop layers in thin power devices. The electrical characteristics of 1200 V IGBTs and diodes provided with such field-stop layers are presented and compared with the characteristics of conventionally processed devices. Moreover, tailoring the field-stop distribution by multi-energy proton implantations offers new opportunities for optimizing the performance of power devices.

The reported diffusion constants for hydrogen in silicon vary over six orders of magnitude. This spread in measured values is caused by the different concentrations of defects in the silicon that has been studied. Hydrogen diffusion is slowed down as it interacts with impurities. By changing the material properties such as the crystallinity, doping type and impurity concentrations, the diffusivity of hydrogen can be changed by several orders of magnitude. In this study the influence of the hydrogen concentration on the temperature dependence of the diffusion in high energy proton implanted silicon is investigated. We show that the Arrhenius parameters, which describe this temperature dependence decrease with increasing hydrogen concentration. We propose a model where the relevant defects that mediate hydrogen diffusion become saturated with hydrogen at high concentrations. When the defects that provide hydrogen with the lowest energy positions in the lattice are saturated, hydrogen resides at energetically less favorable positions and this increases the diffusion of hydrogen through the crystal. Furthermore, we present a survey of different studies on the diffusion of hydrogen. We observed a correlation of the Arrhenius parameters calculated in those studies, leading to a modification of the Arrhenius equation for the diffusion of hydrogen in silicon.

The desaturation and charge recovery behavior for 1200-V RC-IGBTs with diode control is investigated. The low thickness of the drift-region of modern 1200-V IGBTs results in significantly reduced time constants of the diode-control feature. While a low desaturation time constant is well acceptable, the recovery time constant becomes critical when compared to typical locking time requirements of common gate driver units. The impact of different locking times on the overall performance is discussed and a novel device concept for RC-IGBTs is presented which overcomes this issue. The FWD-mode of the novel RC-IGBT is desaturated at a gate-emitter voltage of 0 V allowing for the first time a desaturation pulse pattern which may disregard the locking time requirements of the driving-unit.

Ein Verfahren zum Bilden eines Halbleiterbauelements und ein Halbleiterbauelement werden bereitgestellt. Das Verfahren beinhaltet das Bereitstellen eines Waferstapels (40), der einen Tragerwafer (20), der Graphit aufweist, und einen Bauelementwafer (1, 2) aufweist, der ein Halbleitermaterial mit breiter Bandlucke aufweist und eine erste Seite (21) und eine zweite Seite (22) gegenuber der ersten Seite (21) aufweist, wobei die zweite Seite (22) an dem Tragerwafer (20) befestigt ist, Definieren von Bauelementregionen (D) des Waferstapels (40), teilweises Entfernen des Tragerwafers (20), sodass Offnungen (25) in dem Tragerwafer (20) gebildet werden, die in jeweiligen Bauelementregionen (D) angeordnet sind, und sodass der Bauelementwafer (1, 2) von einem Rest (20') des Tragerwafers (20) gestutzt wird; und Weiterbearbeiten des Bauelementwafers (1, 2), wahrend der Bauelementwafer (1, 2) von dem Rest (20') des Tragerwafers (20) gestutzt bleibt.

In this study we examine proton implanted and subsequently annealed commercially available CZ wafers with the DLTS method. Depth-resolved spreading resistance measurements are shown, indicating an additional peak in the induced doping profile, not seen in the impurity-lean FZ reference samples. The additional peak lies about 10–15μm deeper than the main peak near the projected range of the protons. A DLTS characterization in the depth of the additional peak indicates that it is most likely not caused by classical hydrogen-related donors known also from FZ silicon but by an additional donor complex whose formation is assisted by the presence of silicon self-interstitials.

Two metastable defects with energy levels at Ec-0.28eV and Ec-0.37eV, which previously have been reported in proton implanted- and in proton implanted and annealed crystalline silicon are discussed. Recent results on the peculiar behavior of these defects upon periodical application of two different bias conditions during DLTS measurement are reviewed. Two specifically designed DLTS measurement sequences are proposed in order to further reveal the defects transformation rates and respective activation energies.

– For a conventional proton implantation doping process applied to crystalline silicon comprising proton implantation and subsequent furnace annealing the effect of the substrate temperature set during implantation is examined for temperatures between 50 °C and 200 °C. The formation efficiency of the hydrogen related donors in the maximum of the related doping profiles is shown to linearly increase with the implantation temperature. Regarding the dose rate, a reverted effect is found. The appearing effects are explained by considering the evolution of the initial implantation damage towards a vacancy related precursor species of the hydrogen related donor. Additional information about the implantation temperature dependent defect distribution is gained from Fourier-DLTS results.

A failure mechanism in the edge termination of a 1200V IGBT during overcurrent turn-off is studied with simulations and verified by experiments. The position of the destruction in the experiment can be correlated to the formation of a critical filament in the simulation. The destruction mechanism is investigated in detail. It is only observed if the IGBT enters its current saturation regime. I.e., the IGBT survives a turn-off from the same current level for an increased gate voltage. It is shown that an IGBT provided with a properly-designed High Dynamic Ruggedness (HDR) edge termination structure [1] is no longer susceptible to the destruction mechanism.

Proton (H+) implantations are used in power semiconductor devices to introduce recombination centers (Hazdra et al., Microelectron. J. 32(5), 449-456 (2001)) or to form hydrogen related donor complexes (Zohta et al., Jpn. J. Appl. Phys. 10, 532-533 (1991)). Proton implantations are also used in the 'smart cut' process to generate defects that can be used to cleave thin wafers (Romani and Evans, Nucl. Instrum. Methods Phys. Res. B 44, 313-317 (1990)). However, the implantation damage resulting from H+ implantations is not completely understood. In this study, protons with energies from 400 keV up to 4 MeV and doses up to 10(16) H+/cm(2) were implanted into highly ohmic boron doped m:Cz silicon (100). Electron Beam Induced Current (EBIC) measurements were performed to locally determine the minority charge carrier diffusion length. The diffusion length decreases with increasing implantation dose and incorporated damage. Spreading Resistance Profiling (SRP) measurements were performed to analyze the charge carrier concentration profiles for different annealing procedures. The electrical activation and growth of the defect complexes varies strongly with the annealing parameters. Transmission Electron Microscopy measurements were made to investigate the microscopic structures formed by the high dose implantation processes. Due to the high local damage density resulting from low energy and high dose H+ implants, platelet structures are formed. During high-energy high-dose H+ implantations, the implanted hydrogen generates strain in the crystal lattice resulting in changes in the distances between atomic planes. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim