A δ-doped In0.45Al0.55As/InGaAs metamorphic high-electron-mobility transistor (MHEMT) using an In0.45Ga 0.55As/In0.65Ga0.35 As inverse composite channel has been fabricated successfully and demonstrated. The inverse composite channel significantly reduces Coulomb scattering and consequently improves electron mobility as well as carrier confinement. Experimentally, a high extrinsic transconductance of 321 mS/mm and a drain-source saturation current density of 342mA/ mm are obtained for a 0.65 × 200 μm2 gate at 300 K. Meanwhile, degradation of the studied device, in terms of parameters such as Gm.max, IDSS, and Vth, with increasing temperature is not evident. A positive temperature coefficient of V th, is observed. The measured fT and fmax, for a 0.65-μm-gate device are 41.6 and 53 GHz, respectively. In addition, the studied device also shows good microwave performances in a flat and wide operation region. From VGS = -2.5 to 0.5 V, the values of f T and fmax are still over 33 GHz.
|Number of pages||6|
|Journal||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|Publication status||Published - 2005 Aug 5|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)