Low current wideband amplifier using 0.2 /spl mu/m gate MODFET fabricated by using phase-shift lithography
We have developed wideband amplifier that can keep over 10 dB gain at the drain voltage/current of 2 V/10 mA in the frequency range from 100 MHz to 3 GHz. The fabricated IC achieved low noise figure and high IP3 (output) of 1.4 dB and 30 dBm at 800 MHz, respectively. The present IC employs 0.2 /spl mu/m gate delta-doped MODFET structure fabricated by using phase-shift lithography.
Advanced GaAs-MMIC process technology using high-dielectric constant thin film capacitors by low-temperature RF sputtering method
The authors have developed a new GaAs-MMIC process technology using the low-temperature RF sputtered SrTiO/sub 3/ thin film capacitors which were combined with WSi-gate self-aligned FETs (SAFETs). The SrTiO/sub 3/ film with high dielectric constant (/spl epsi//sub r/) over 100 and low leakage current density under 10/sup -6/A/cm/sup 2/ at 1 MV/cm was obtained by RF sputtering method with the temperature range of 200/spl sim/300/spl deg/C. This SrTiO/sub 3/ capacitor exhibited no /spl epsi///sub r/ change up to 3.0 GHz, and low insertion losses of 0.29 dB and 0.05 dB were obtained for 32 pF-capacitor (S=10,000 /spl mu/m/sup 2/) at 0.2 GHz and 1.0 GHz, respectively. By integrating these on-chip SrTiO/sub 3/ bypass-capacitors into GaAs-IC, the parasitic inductance of the source-to-ground interconnection is successfully reduced, and the enhanced gain characteristic was obtained for self-biased amplifier circuit.<<ETX>>
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).