Heterojunction Bipolar Transistor

Abstract

A heterojunction bipolar transistor, comprising an elongated base mesa, an elongated base electrode, two elongated emitters, an elongated collector, and two elongated collector electrodes. The elongated base electrode is formed on the base mesa along the long axis of the base mesa, and the base electrode has a base via hole at or near the center of the base electrode. The two elongated emitter are formed on the base mesa respectively at two opposite sides of the base electrode, and each of two emitters has an elongated emitter electrode formed on the emitter. The elongated collector is formed below the base mesa. The two elongated collector electrodes are formed on the collector respectively at two opposite sides of the base mesa.

What is claimed is: 
     
         1 . A heterojunction bipolar transistor, comprising:
 an elongated base mesa having a long axis and a short axis;   an elongated base electrode having a long axis and a short axis, formed on the base mesa with the long axis of the base electrode essentially parallel to the long axis of the base mesa, and the base electrode having a base via hole at or near the center of the base electrode;   two elongated emitters formed on the base mesa respectively at two opposite sides of the base electrode along the long axis of the base electrode, each emitter having an elongated emitter electrode formed on the emitter;   an elongated collector formed below the base mesa; and   two elongated collector electrodes formed on the collector respectively at two opposite sides of the base mesa along the long axis of the base mesa.   
     
     
         2 . The heterojunction bipolar transistor according to  claim 1 , wherein the base electrode is formed on the base mesa with the long axis of the base electrode essentially parallel to the long axis of the base mesa at or near the center of the short axis of base electrode. 
     
     
         3 . The heterojunction bipolar transistor according to  claim 1 , wherein the base mesa having a length and a width, and the ratio of the length to width is between 1.2:1 and 15:1. 
     
     
         4 . The heterojunction bipolar transistor according to  claim 3 , wherein the base mesa, the emitter electrodes, and the collector electrodes are in rectangular shapes. 
     
     
         5 . The heterojunction bipolar transistor according to  claim 3 , wherein the base mesa, the emitters, and the collector are in bent elongated shapes each having a bending position, and the bending position located at or near the center of the elongated shape. 
     
     
         6 . The heterojunction bipolar transistor according to  claim 2 , wherein the base mesa, the emitter electrodes, and the collector electrodes are in rectangular shapes. 
     
     
         7 . The heterojunction bipolar transistor according to  claim 2 , wherein the base mesa, the emitters, and the collector are in bent elongated shapes each having a bending position, and the bending position located at or near the center of the elongated shape. 
     
     
         8 . The heterojunction bipolar transistor according to  claim 1 , wherein the base mesa, the emitter electrodes, and the collector electrodes are in rectangular shapes. 
     
     
         9 . The heterojunction bipolar transistor according to  claim 1 , wherein the base mesa, the emitters, and the collector are in bent elongated shapes each having a bending position, and the bending position located at or near the center of the elongated shape. 
     
     
         10 . The heterojunction bipolar transistor according to  claim 1 , wherein the base mesa, the emitters, and the collector are in bent elongated shapes each having a bending position, and the bending position located at or near the center of the elongated shape with a bending angle of 90°. 
     
     
         11 . A heterojunction bipolar transistor, comprising:
 an elongated base mesa having a long axis and a short axis;   an “H” shaped emitter formed on the base mesa, the “H” shaped emitter having two recesses respectively on two opposite sides of the “H” shape, and the emitter having two elongated emitter electrodes formed on the “H” shaped emitter;   two base electrodes formed on the base mesa respectively at the two recesses of the “H” shaped emitter, and each of the base electrodes having a base via hole at or near the center of the base mesa;   an elongated collector formed below the base mesa; and   two elongated collector electrodes formed on the collector respectively at two opposite sides of the base mesa along the long axis of the base mesa.   
     
     
         12 . The heterojunction bipolar transistor according to  claim 11 , wherein the recesses of the “H” shaped emitter are provided at or near the center of the short axis of base electrode. 
     
     
         13 . The heterojunction bipolar transistor according to  claim 11 , wherein the base mesa having a length and a width, and the ratio of the length to width is between 1.2:1 and 15:1. 
     
     
         14 . The heterojunction bipolar transistor according to  claim 11 , wherein the base mesa, the emitter electrodes, and the collector electrodes are in rectangular shapes. 
     
     
         15 . The heterojunction bipolar transistor according to  claim 12 , wherein the base mesa, the emitter electrodes, and the collector electrodes are in rectangular shapes. 
     
     
         16 . The heterojunction bipolar transistor according to  claim 13 , wherein the base mesa, the emitter electrodes, and the collector electrodes are in rectangular shapes.