In this paper, we report an L g = 25 nm InGaAs/InAlAs HEMT on InP substrate that delivers excellent high-frequency characteristics. The device exhibited a value of maximum transconductance (g m_max) = 2.8 mS μm−1 at V DS = 0.8 V and on-resistance (R ON) = 279 Ω μm. At I D = 0.56 mA μm−1 and V DS = 0.5 V, the same device displayed an excellent combination of f T = 703 GHz and f max = 820 GHz. To the best of the authors’ knowledge, this is the first demonstration of a transistor with both f T and f max over 700 GHz on any material system.

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Absfrad.In this paper, the inverse mapping method is applied to the federate control of C N C machines to improve the productivity while preserving the machining precision. The contour error, which is directly related to the machining precision, is computed from a recently developed contour e r r o r mo.del with the variable size window. The feedrate is iteratively calculated following the Lyapunov function within a tolerable error bound. The relationship between the feedrate and the contour e r r o r used in the inverse mapping is identified by using a multi-layer neural network. Simulations on circular and involute contours demonstrate the performance of the proposed method.