A novel GaAs flip-chip power MODFET with a spike-gate structure has been developed for high-gain and high-efficiency operation under extremely low supply voltages. The spike-gate MODFET is featured by a unique gate structure that has almost zero effective gate length. The spike gate provides both a low on-resistance of 1.5 Ω mm and a high transconductance of 280 mS/mm without increasing the drain conductance. The flip-chip bonding, with an Au-Sn alloy system, has been used for mounting of the spike-gate power MODFET on an AlN substrate. The thermal resistance of the flip-chip power MODFET is 12°C/W which is lower than that of a conventional wire-bonded MODFET. The power-added efficiency (PAE) of 71% at the output power of 30.0 dBm can be obtained even when the supply voltage is reduced to 1.5 V. By eliminating parasitic wire inductance, the linear gain of the MODFET is 2 dB higher and the PAE is 5% higher than that of the conventional wire-bonded MODFET.
|Number of pages||7|
|State||Published - 1 Jan 1999|
|Event||Proceedings of the 1998 3rd Tropical Workshop on Heterostructure Microelectronics for Information Systems Applications (TWHM-ISA '98) - Hayama-Machi, Jpn|
Duration: 30 Aug 1998 → 2 Sep 1998