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>>
Sub-Half-Micron i-Line Lithography by Use of LMR-UV Resist
Negative photoresist, LMR-UV, has been developed for i-line lithography. It resolves isolated 0.3 µm space and 0.35 µm hole patterns of 1.0 µm thickness by using a 0.42-numerical-aperture i-line reduction projection aligner. LMR-UV gives overhung profiles because of its large absorption coefficient of 3.8 µm-1 at the i-line. New phase-shifting mask patterns which are adapted to isolated space and hole patterns for negative resist have been developed. By use of this mask, LMR-UV clearly resolves 0.25 µm space and 0.3 µm hole patterns by using the i-line aligner. This phase-shifting mask improves both resolution and focus margin.