133 research outputs found
Electricâfield dependence of interband transitions in In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As single quantum wells by roomâtemperature electrotransmittance
Roomâtemperature electrotransmittance has been used in order to investigate the interband excitonic transitions in a 250âĂ
âthick In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As singleâquantumâwell system as a function of an externally applied electric field. Parity forbidden transitions, involving conductionâband states with quantum numbers up to n=5, which become more pronounced at high electric fields were observed. The groundâstate and the forbidden transitions showed a significant red shift due to the quantum confined Stark effect. A comparison with previously reported results on thinner InGaAs/InAlAs quantum wells indicated that the wideâwell sample exhibits the largest shift, as expected from theory. Despite the appreciable Stark shift, the rather large, fieldâinduced linewidth broadening and the relatively low electric field at which the groundâstate exciton is ionized poses limitations on using this wideâquantumâwell system for electroâoptic applications
High Power Self-Aligned, Trench-Implanted 4H-SiC JFETs
The process technology for the fabrication of 4H-SiC trenched-implanted-gate 4HâSiC vertical-channel JFET (TI-VJFET) has been developed. The optimized TIVJFETs have been fabricated with self-aligned nickel silicide source and gate contacts using a process sequence that greatly reduces process complexity as it includes only four lithography steps. A source-pillars sidewall oxidation and subsequent removal of the metallization from the top of the sidewall oxide ensured isolation between gate and source. Optimum planarization of the source pillars top has been performed by cyclotene spin coating and etch back. The effect of the channel geometry on the electrical characteristics has been studied by varying its length (0.3 and 1.2ÎŒm) and its width (1.5-5ÎŒm). The voltage blocking exhibits a triode shape, which is typical for a static-induction transistor (SIT) operation. The transistors exhibited high ON current handling capabilities (Direct Current density >1kA/cm2) and values of RON ranging from 6 - 12 mΩâącm2 depending on the channel length. Maximum voltage blocking was 800V limited by the edge termination. The maximum voltage gain was 51. Most transistors were normally-on. Normally-off operation has been observed for transistors lower than 2ÎŒm channel width (mask level) and deep implantation
Silicon carbide- from synthesis to application: a review
This paper provides a review of the synthesis techniques that are used to produce nanostructured silicon carbide. The synthesis methods, consisting of carbothermal reduction, chemical vapor deposition, laser ablation, sol-gel and microwave heating are described. The silicon carbide properties and application are also explained. The paper then discusses the limitations of previous studies which involved complicated equipment and processes, that limit their further application and act as a barrier to further research and development in many fields
Advancing silicon carbide electronics technology I
The rapidly advancing Silicon Carbide technology has demonstrated a great potential in high-power low-loss semiconductor electronics. High thermal stability and outstanding chemical inertness make SiC an excellent material for development of high temperature electronics and semiconductor devices operating in harsh environment. Keywords: Silicon Carbide Technology, Semiconductor Devices, SiC Device Fabrication, SiC Device Characterization, SiC Surface Cleaning, SiC Surface Etching, Electrical Characterization of SiC, Ohmic Contacts to SiC, Contact Resistivity Analysis, Ohmic Contact Fabrication, Metallization Schemes, Thermal Stability of Ohmic Contacts to SiC, Schottky Contacts to SiC, Schottky Barrier Formation, Schottky Diodes, Junction Barrier Schottky Diodes, Si/ SiC Heterojunction Diodes, Schottky Barrier Inhomogeneity in SiC, SiC Power Electronics, Temperature/Light Sensors, SiC Switching Devices, High Temperature Electronics, High Frequency Electronics, Thermal Stability of SiC
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