Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a first barrier layer on the buffer layer; forming a first hard mask on the first barrier layer; removing the first hard mask and the first barrier layer to form a recess; forming a second barrier layer in the recess; and forming a p-type semiconductor layer on the second barrier layer.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a first barrier layer on the buffer layer; forming a first hard mask on the first barrier layer; removing the first hard mask and the first barrier layer to form a recess; forming a second barrier layer in the recess; and forming a p-type semiconductor layer on the second barrier layer.

Abstract: A system and method for controlling a centrifuge which receives a mixture of liquid and solid particles and separates the liquid from the solid particles. A bowl, along with a conveyor extending inside the bowl, are rotated and the speed of, and the torque applied to, the bowl and the conveyor are detected and corresponding output signals are generated. A variable speed drive pump is provided for pumping the flow of the mixture to the centrifuge. A computer responds to the output signals and controls the speed of the bowl and the conveyor as well as the operation of the pump to attain predetermined optimum operating conditions of the centrifuge.

Abstract: A system, method and computer program for controlling a centrifuge which receives a mixture of liquid and solid particles and separates the liquid from the solid particles. A bowl, along with a conveyor extending inside the bowl, are rotated at different speeds and the speed of, and the torque applied to, the bowl and the conveyor are detected and corresponding output signals are generated. A meter is provided for metering the flow of the mixture to the centrifuge and generating corresponding output signals. A computer responds to instructions from computer programs and controls the speed of the bowl and the conveyor as well as the flow of the mixture and a diluting agent to the centrifuge in response to the output signals in a manner to attain predetermined predetermined optimum operating conditions of the centrifuge.