RF power-generator

The RF power-generator typically works at frequencies of w = 2.6-3.2 MHz with a power of 40-80 kW, depending on the desired crystal diameter. Till now, such generators only work with an industrial electron power tube (tri-ode), which is robust, but has a limited total operating time. The RF output parameters (w, U, I) of the self-excited generator are defined by the tank... 

IM 101 rf power generator operating at 13.56 MHz. Chamber pressure was monitored with an MKS Baratron l pe 90H-1 capacitance manometer. The reactor was evacuated to less than 10 Tbrr with a diffusion pump prior to introduction of monomer. During the actual deposition, a mechanical pump with an in-line liquid nitrogen cold trap was used to maintain moncmier and carrier gas flow. 

RF power generation, transmission, monitoring and control system ... 

Precisely controllable rf pulse generation is another essential component of the spectrometer. A short, high power radio frequency pulse, referred to as the B field, is used to simultaneously excite all nuclei at the T,arm or frequencies. The B field should ideally be uniform throughout the sample region and be on the order of 10 ]ls or less for the 90° pulse. The width, in Hertz, of the irradiated spectral window is equal to the reciprocal of the 360° pulse duration. This can be used to determine the limitations of the sweep width (SW) irradiated. For example, with a 90° hard pulse of 5 ]ls, one can observe a 50-kHz window a soft pulse of 50 ms irradiates a 5-Hz window. The primary requirements for rf transmitters are high power, fast switching, sharp pulses, variable power output, and accurate control of the phase. 

The etch experiments were performed using a commercial ICP etcher equipped with an ICP source and a load lock. The substrate susceptor was cooled by He through a chilled fluid. The coil, which was connected to a 13.56 MHz RF power supply, was located on the lid of a ceramic chamber to generate a high density plasma. A bias voltage induced by RF power at... 

The lower electrode is coupled via a fl-type matching network to a 13.56-MHz generator. This network provides power matching between the RF power cable (50 2) and the plasma. Power levels are between 1 and 100 W, or between 6 and 600 mW/cm, using the area of the powered electrode. 

Armaou and Christofides (1999) present a two-electrode design for the deposition of 500-A films on an 8-cm wafer, which sits on top of the lower electrode, as shown in Fig. 10.4-2. The reactor is fed with 10% SiEE (silane) in He at 1 torr through a showerhead. An RF power source, at 13.56 MHz frequency, is used to generate the plasma, which is transported by convection and diffusion to the surface of the wafer where reaction occurs to deposit amorphous silicon. Electrical heating elements are positioned below the wafer and along the walls to achieve a uniform temperature of the plasma and wafer at 500 K. 

Shaped pulses are created from text files that have a line-by-line description of the amplitude and phase of each of the component rectangular pulses. These files are created by software that calculates from a mathematical shape and a frequency shift (to create the phase ramp). There are hundreds of shapes available, with names like Wurst , Sneeze , Iburp , and so on, specialized for all sorts of applications (inversion, excitation, broadband, selective, decoupling, peak suppression, band selective, etc.). The software sets the maximum RF power level of the shape at the top of the curve, so that the area under the curve will correspond to the approximately correct pulse rotation desired (90°, 180°, etc.). When an experiment is started, this list is loaded into the memory of the waveform generator (Varian) or amplitude setting unit (Bruker), and when a shaped pulse is called for in the pulse sequence, the amplitudes and phases are set in real time as the individual rectangular pulses are executed. 

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