公开(公告)号：US5448087A

公开(公告)日：1995-09-05

申请号：US876199

申请日：1992-04-30

申请人： Swight C. Streit ,  Aaron K. Oki

发明人： Swight C. Streit ,  Aaron K. Oki

IPC分类号： H01L29/10 ,  H01L29/737 ,  H01L29/161 ,  H01L29/205 ,  H01L29/225

CPC分类号： H01L29/7371 ,  H01L29/1004

摘要： A heterojunction bipolar transistor with an exponentially graded base doping is disclosed, in addition to a technique for fabricating the transistor. In accordance with the preferred embodiment, the transistor employs a base with an exponentially graded Beryllium doping which varies from 5.times.10.sup.19 cm.sup.-3 at the base-emitter junction to 5.times.10.sup.18 cm.sup.-3 at the base-collector junction. The built-in field due to the exponentially graded doping profile significantly reduces base transit time despite bandgap narrowing associated with high base doping. Compared to devices with the same base thickness and uniform base doping, the cut off frequency is increased and the maximum frequency of oscillation is also increased. Also, consistently higher common emitter current gain results even though the Gummel number is twice as high and the base resistance is reduced by 40%.

摘要翻译： 除了制造晶体管的技术之外，还公开了具有指数梯度的基极掺杂的异质结双极晶体管。 根据优选实施例，晶体管采用具有指数级渐变的铍掺杂的基极，其在基极 - 集电极结处的基极 - 发射极结处从5×10 19 cm -3变化到5×10 18 cm -3。 由于具有指数梯度的掺杂特性，内置场可显着降低基极通过时间，尽管与高基极掺杂相关的带隙变窄。 与具有相同基底厚度和均匀基极掺杂的器件相比，截止频率增加，振荡的最大频率也增加。 此外，尽管Gummel数量是两倍高，基极电阻降低了40％，但始终更高的公共发射极电流增益。