Method of Modulating Alloy Concentration in the Base of Heterojunction Bipolar Transistors
Original Publication Date: 2003-Apr-04
Included in the Prior Art Database: 2003-Apr-04
A method of enhancing the graded base structure of a high performance SiGe heterojunction bipolar transistor (HBT) through the use of Atomic Layer Deposition (ALD) is described. ALD allows for accurate placement of germanium and boron dopants within the graded base structure. Such improvements in the base profiles of HBTs can enhance the base-to-collector current amplification factor (b), improve collector currents (Ic), lower base resistance Rb, and increase operation frequencies (fmax), compared to HBTs fabricated with a silicon base.