| 摘要 |
In a method of forming a base region and an emitter window for a silicon bipolar transistor on a silicon substrate, comprising forming an intrinsic base layer containing SiGe, on top of the substrate, forming a layer of SiO2 on the intrinsic base layer, forming an extrinsic base layer containing Si, on top of the SiO2 layer, forming a layer of a dielectric on top of the extrinsic base layer, patterning the emitter window on top of the dielectric, and etching out the emitter window selectively down to the SiO2 layer, the structure is exposed to HF to remove the SiO2 layer in the emitter window, and Si is selectively deposited on the exposed intrinsic base layer and exposed side walls of the extrinsic base layer as well as in cavities created in the SiO2 layer and the dielectric by the exposure to HF to establish contact between the extrinsic base layer and the intrinsic base layer. |
