Laser-Induced Single Event Transients in Local Oxidation of Silicon and Deep Trench Isolation Silicon-Germanium Heterojunction Bipolar Transistors

We present a study on the single event transient (SET) induced by a pulsed laser in different silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) with the structure of local oxidation of silicon (LOCOS) and deep trench isolation (DTI). The experimental results are discussed in detail and it is demonstrated that a SiGe HBT with the structure of LOCOS is more sensitive than the DTI SiGe HBT in the SET. Because of the limitation of the DTI structure, the charge collection of diffusion in the DTI SiGe HBT is less than that of the LOCOS SiGe HBT. The SET sensitive area of the LOCOS SiGe HBT is located in the collector-substrate (C/S) junction, while the sensitive area of the DTI SiGe HBT is located near to the collector electrodes.