Papers by Keyword: p-Type Doping

Abstract: Experimental results presented in this contribution demonstrate that adding HCl to the SiC CVD process is not only an efficient way to suppress the Aluminum memory effect but may also be considered as a powerful tool for fine tuning of intentional Al incorporation in 3C-SiC and 4H-SiC thin films. The approach is easy to implement and seems more reliable than changing TMA bubbling/dilution parameters during the growth. An ad-hoc phenomenological model is proposed to explain the correlation between the HCl supply and Al incorporation.

Abstract: The silicon carbide cubic polytype (3C-SiC) is a material of choice to fabricate microelectromechanical systems. However, the mechanical properties of 3C-SiC-based devices are severely linked to the stress of the involved 3C-SiC material. Moreover, the stress level can hamper completing microsystems. As a consequence, in this study, we considered the influence of aluminum (Al) doping towards the mechanical properties of 3C-SiC epilayers and demonstrated a noticeable reduction of the Young’s modulus with a high Al incorporation.

Abstract: The activation energy for the electrical activation of 1x10¹⁹ cm^-3 and of 1x10²⁰ cm^-3 ion implanted Al in 4H-SiC has been estimated. Ion implantation temperature and dose rate were in the range 430-500°C and around 10¹¹ cm²s^-1, respectively. Post implantation annealing temperatures varied between 1500 °C and 1950 °C. The annealing time per each annealing temperature was sufficiently long that the sheet resistance of the implanted layer could be equal to the stationary value at the applied annealing temperature. The Arrhenius plots of the room temperature sheet resistances with respect to the post implantation annealing temperatures featured an exponential trend for both the implanted Al concentrations. The activation energies of these plots are the activation energy for placing an implanted Al atom in a substitutional site, i.e. the electrical activation energy. Activation energies around 1 eV, equal within errors for the two implanted Al concentrations, were found.

Abstract: The silicon carbide cubic polytype (3C-SiC) is perfectly appropriate to fabricate microelectromechanical systems. However, for such applications, the stress can largely influence both the fabrication of 3C‑SiC‑based microsystems and their related mechanical properties. Accordingly, in this study, we investigated the influence of strong aluminum incorporation towards the mechanical properties of 3C-SiC epilayers grown on silicon substrates.

Abstract: SiC-powered devices which reduce the power loss, size, and weight of power converters are gradually appearing in the power electronics market. From now on, cost reduction and quality improvement of SiC epitaxial wafers is required to further increase their popularity. This paper describes the state of development of mass production of the epi-wafer at Showa Denko K. K.

Abstract: The electrical activation of 1×10²⁰ cm^-3 implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature. The minimum annealing time for reaching stationary electrical at fixed annealing temperature has been found. The samples with stationary electrical activation have been used to estimate the thermal activation energy for the electrical activation of the implanted Al.

Abstract: After presenting an exhaustive experimental study of aluminum incorporation in epitaxial 4H-SiC and 3CSiC films grown by chemical vapor deposition (CVD), we focalize once more on what is called site competition effects. We observed that the influence of C/Si ratio on dopant (Al, N) incorporation in SiC was qualitatively different depending on whether the growth experiments were performed in “low temperature” (LT) or “high temperature” (HT) regime. Partial explanation of observed phenomena basing on thermal evolution of carbon coverage of SiC surface is proposed.

Abstract: This paper presents a high-quality 100/150 mm p-type 4H-SiC epitaxial wafer prepared by chemical vapor deposition; this wafer is suitable for high-voltage bipolar device applications. The density of killer defects for bipolar devices including downfalls, triangular-shaped defects, and basal plane dislocations (BPDs), is less than 0.1 cm^-2 in the proposed 100 mm n/p multilayer epitaxial wafer. The in-plane thickness and doping uniformity of the 150 mm p-layer is 3.0% and 11.0%, respectively. The doping concentration of the p-layer can be controlled in the 1E+16 cm^-3 to 1E+19 cm^-3 range.

Abstract: P-type 4H-SiC layers have been obtained by different 400°C Al+ ion implantation processes of semi insulating 4H-SiC wafers and identical 1950°C/5 min post implantation annealing. Implanted Al+ concentration have been 4.7×1018, 9.3×1018, and 4.7×1019 cm-3, thickness of the implanted layer about 630 nm. Electrical characterizations have been performed in the temperature range 100 – 580 K. With decreasing temperature, the onset of a hole conduction through an impurity band has been seen for all the specimens.

Abstract: In this work, the achievement and characterization of boron-doped nanocrystalline diamond films is presented. A series of experiments varying boron doping levels from 2,000 to 30,000 ppm and film growth times during 6, 10 and 16 h were performed. These films were analyzed by Scanning Electron Microscoy (SEM), Atomic Force Microscopy (AFM), Raman spectroscopy and Cyclic Voltammetry (CV) measurements. The results showed that the films presented two morphologies: ultra and nanocrystalline diamond. From Raman spectroscopy, the doping level increase for all the films, independent of growth time, increased the boron acceptor number and it was confirmed by Mott-Schottky plot (MSP). Electrochemical response showed the influence of boron content in the work potential window, mainly for films grown during 6 h. However, the reversibility was almost independent on the boron content for samples grown during 16 h.