I. Introduction
The DEMAND for high bit rate optical communication, software radio, and millimeter wave applications requires the development of devices with high cutoff frequencies. One candidate for these applications is the InP-based high-electron mobility transistors (HEMT). This device has demonstrated a very high RF performance with a cutoff frequency of extrinsic current gain of 562 GHz, obtained with a InGaAs–InAlAs pseudomorphic HEMT on InP [1]. This result has been achieved by reduction of the gate length to 25 nm. However, the maximum oscillation frequency is only 330 GHz [1]. Though is interesting for digital circuits used in optical communication systems [2], an improvement of the maximum oscillation frequency is required and preferable for the realization of some analog circuits, for which a high power gain is the main objective. Furthermore, shortening gate length requires a reduction of gate-to-channel distance to keep a constant aspect ratio and to avoid short-channel effects [3]. This scaling down rule is not only limited by the gate tunnel current, but also by the degradation of the effective gate length related to the depletion in the recessed regions. So, to keep on increasing continuously , it will be necessary to find an alternative solution based on a change of the actual technology. This technological change can be made by using the transferred substrate technique, already used in double-gate (DG) silicon-on-insulator (SOI)-MOSFET [4], TS-HBT [5], and TS-HEMT [6]. We propose, using a transferred Cross section of the DG HEMT using transferred substrate technique. DG HEMT layer structure. substrate technique, the realization of DG HEMTs, with one gate being placed on each side of the conductive channel (Fig. 1). Due to the better charge control efficiency, a good pinchoff behavior and a high transconductance are expected.