在1972年国际电子器件会议上,日本富士通公司发表了一种新的半导体制造技术——掺杂多晶硅工艺,该工艺可应用于超高速集成电路和微波晶体管制作。在电流型逻辑超高速集成电路及微波晶体管中,由于电极条很窄(例如莫托洛拉公司的MECLⅢ,单门传递延迟时间1毫微秒,发射极条宽为9000埃～1微米),一般都用泡发射极工艺。亦即在形成微波晶体管及ECL电路的发射极扩散层时,由化学汽相淀积法生成掺杂氧化层,经热扩散后,由泡发射极工艺开发射极窗孔,然后形成铝电极。泡发射极工艺是利用掺杂的氧化层(掺杂SiO_2)与不含杂质的二氧化硅之间腐蚀速度的不同,从而可不采用光刻掩蔽(免去发射极光刻)直接腐蚀出发射极 At the 1972 International Electronics Conference, Japan’s Fujitsu Ltd. announced a new semiconductor manufacturing technology - doped polysilicon process, the process can be applied to high-speed integrated circuits and microwave transistors. In current-type logic super-high speed integrated circuits and microwave transistors, since the electrode strip is very narrow (eg, MECL III from Motorola, one-way transfer delay time of 1 nanosecond and emitter width of 9000 angstroms to 1 micrometer) Generally use bubble emitter process. That is, when forming the emitter diffusion layer of the microwave transistor and the ECL circuit, a doped oxide layer is formed by the chemical vapor deposition method, and after the thermal diffusion, the emitter window is formed by the bubble emitter process, and then the aluminum electrode is formed. The bubble emitter process utilizes the difference in etching rate between the doped oxide layer (doped SiO 2) and the impurity-free silicon dioxide so that the emitter can be etched directly without using photolithographic masking (without emitter lithography)