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.
0.15 /spl mu/m T-shaped gate fabrication for GaAs MODFET using phase shift lithography
A new fabrication process of GaAs MODFETs with 0.15 micron T-shaped gate has been developed by using phase shift lithography. Sub-quarter micron footprints of T-shaped gates are defined as line patterns by PEL (pattern-edge line) method using chemically stable positive photoresist. Parasitic capacitances such as C/sub gs/ and C/sub gd/ are also reduced by the air-gap incorporated in the present process. An implemented GaAs MODFET exhibited the NF of 0.36 dB and the gain of 11.5 dB at the frequency of 12 GHz.
A DUV-Defined-Negative Resist/EB-Defined-Positive Resist Two-Layer Resist System for the Fabrication of T-Shaped Gate
We have developed a DUV-defined-negative resist/EB-defined-positive resist two-layer resist system to fabricate T-shaped gates of GaAs MESFET devices. In this resist system, the head of the T-shaped gate is fabricated in the top layer negative resist using a deep-UV exposure and the foot of the T-shaped gate is fabricated in the bottom layer positive resist using an e-beam exposure. Resist profiles are easily controlled because exposures and developments of the top and bottom layers are completely separated. A sub quarter-micron T-shaped gate with the head of the width of more than one micron was successfully fabricated by using this two-layer resist system. This two-layer resist system has wide applicablity for the fabrication of GaAs MESFET devices.