Title :
Emitter-ballasting-resistor-free SiGe microwave power heterojunction bipolar transistor
Author :
Jinshu Zhang ; Hongyong Jia ; Pei-Hsin Tsien ; Tai-Chin Lo
Author_Institution :
Inst. of Microelectron., Tsinghua Univ., Beijing, China
fDate :
7/1/1999 12:00:00 AM
Abstract :
The emitter ballasting resistor is used to equalize the current distribution between the emitter stripes in power transistor, but it will degrade the output power, power gain, and power added efficiency. Experimental results indicate that the current gain of uniform-base SiGe heterojunction bipolar transistors (HBTs) decreases with the increase of the temperature above 160 K, so the current distribution is equalized by itself to some extent. Therefore, the microwave power SiGe HBTs without emitter ballasting resistor were fabricated for the first time, and the continuous output power of 5 W and power added efficiency of 63% were obtained under Class C operation at a frequency of 900 MHz. Hence, the emitter current density of the SiGe HBT´s with emitter width of 6 μm is 0.79 A/cm.
Keywords :
Ge-Si alloys; current density; heterojunction bipolar transistors; microwave bipolar transistors; power bipolar transistors; semiconductor materials; 5 W; 6 micron; 63 percent; 900 MHz; Class C operation; SiGe; current gain; emitter current density; microwave power heterojunction bipolar transistor; output power; power added efficiency; power gain; Current distribution; Degradation; Electronic ballasts; Germanium silicon alloys; Heterojunction bipolar transistors; Power generation; Power transistors; Resistors; Silicon germanium; Temperature distribution;
Journal_Title :
Electron Device Letters, IEEE
