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RF Power
Ceres Crown Series RF power generator provides accurate and high quality with wide variety of models,friendly operation mode and multiple communication interface, can suit to most of plasma - based application 
 
DC Power
Ceres Diamond Series DC power supplier has high performer in basic magnetron sputtering, DC sputtering with RF bias, it provide high quality, best customer control interface for your process.
 
MF Power
  CERES RPS Series MF power supplier has high performer in basic magnetron sputtering, CVD and PECVD, it provide high quality, best customer control interface for your process.
 
IMI
Ceres IMI Series RF Impedance Measuring Instrument 
 
About us
Ceres Renewable Energy Technology Inc is a diversified hi-tech enterprises located in California ,
Focusing on the designs RF Power supplies, Tuner, DC Power, MF power ,Air Plasma Source ...for Advanced Plasma system.

We bulit up the power supplier R&D center at california since 2003. we always take client customized as our design concept. Our product Cover semiconductor,
Flat-panel display , Solar photovoltaic And  other
advanced plasma Application.
 
News
Chromium/aluminium n-electro..
Researchers based in China have been applying reflective n-type electrode metal structures to boost light extraction in 280nm-wavelength deep-ultraviolet light-emitting diodes (DUV-LEDs) [Yang Gao et al, IEEE Transactions on Electron Devices, published online 21 May 2019]. One of the big challenges for sub-300nm DUV devices is pushing the efficiency above 10%. The work by Huazhong University of Science and Technology and University of Science and Technology of China used a chromium/aluminium combination to enhance reflection of the electrodes on the n-type aluminium gallium nitride (AlGaN) contact layer of the LEDs. While the chromium absorbs DUV radiation, aluminium is highly reflective. The researchers explain the need for chromium in the electrode: “If we only adopt the Al layer as the n-type electrode, it is almost impossible to form an ohmic contact with the Al-rich n-AlGaN. Therefore, a Cr metal layer must be introduced before the deposition of the Al layer to form an ohmic contact and improve the electrical performance.” The researchers see DUV applications in sterilization, water/air purification, medical and bio-related equipment. Competing mercury-lamp devices have drawbacks such as system fragility and bulk, along with short lifetime and low efficiency. And, of course, mercury is highly toxic. The DUV-LED material was grown by metal-organic chemical vapor deposition (MOCVD) on c-plane sapphire. The buffer consisted of 2μm of AlN. Undoped Al0.55Ga0.45N was used for strain release before a silicon-doped n-Al0.55Ga0.45N contact layer. The light-emitting active region contained five 2.5nm Al0.37Ga0.63N quantum wells separated by 12.5nm Al0.51Ga0.49N barriers. The p-side of the device consisted of magnesium-doped  p-Al0.7Ga0.3N and p-GaN contact layers. Figure 1: Schematic of flip-chip DUV-LED device. The fabrication process was designed to create flip-chips with the DUV light emerging mainly through the sapphire substrate since the bandgap of p-GaN is less than that of the photon energy (Figure 1). The relatively narrow p-GaN gap makes it highly absorbing of the DUV. Unfortunately, magnesium-doping of high-Al-content AlGaN results in very low enhancement of the hole concentration at room temperature due to a high activation energy. DUV-LED fabrication began with inductively coupled plasma etch to expose the n-AlGaN contact layer. The reflective n-electrode consisted of chromium/aluminium/titanium/gold (Cr/Al/Ti/Au) deposited by electron-beam evaporation. The thicknesses of the aluminium, titanium and gold layers were 120nm, 40nm and 60nm, respectively. The chromium thickness varied between 1nm and 20nm. The n-electrode was annealed at 850°C for 30 seconds in nitrogen. The p-electrode consisted of nickel/gold/nickel/gold. An LED with 2.5nm chromium in the n-contact had the lowest turn-on voltage of 4.7V (LED-2). The same device also had the lowest contact resistance. The ideality factor of the devices was around 5.31. Figure 2: (a) LOP versus injected current for five fabricated DUV-LED devices. (b) EQE in terms of current. Inset: corresponding injection current to achieve peak EQE. LED-3 and LED-4 had 5nm and 10nm Cr, respectively. In terms of light output power (LOP) at a given current injection, the device with 1nm chromium in the reflector (LED-1) gave the highest value (Figure 2). At 180mA injection, the output power was 40.9% higher than that for the LED with the thickest chromium layer – LED-5 with 20nm Cr. The researchers suggest that the higher turn-on voltage and contact resistance of LED-1 versus LED-2 could be due to the chromium layer being too thin to form the high-quality Al-Cr and Cr-N alloys needed for ohmic contact. The higher light output is attributed to the high reflectivity of the aluminium layer. The peak external quantum efficiency (EQE) for LED-1 was 25.4% greater than that of LED-5. The corresponding figure for LED-2 was 17.9%. The current injection point of the peak efficiency varied with device: 74mA for LED-1, 78mA for LED-2, and 60mA for LED-5. The researchers explain the higher current injection for LED-2 as being due to its superior ohmic contact and electrical behavior. “Normally, a lower contact resistance or better ohmic contact can definitely improve current spreading and thus higher current injection efficiency,” the team writes. The reflectivity of Cr/Al metal stacks on sapphire was measured at 280nm center wavelength and compared with the results from an unalloyed Al layer. The relative reflection for 1nm Cr was 93.1%, and that for 2.5nm Cr was 82.2%.
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