A SiGe HBT formed on a silicon substrate is disclosed. An active area is isolated by field oxide regions; a collector region is formed in the active area and extends into the bottom of the field oxide regions; pseudo buried layers are formed at the bottom of the field oxide regions, wherein each pseudo buried layer is separated by a lateral distance from the active area and connected to a lateral extension part of the collector region; first deep hole contacts are formed on top of the pseudo buried layers in the field oxide regions to pick up collector electrodes; a plurality of second deep hole contacts with a floating structure, are formed in the field oxide region on top of a lateral extension part of the collector region, wherein N-type implantation regions are formed at the bottom of the second deep hole contacts.