【摘要】 为了有效改善射频功率HBT的热不稳定性、消除自加热效应对功率器件电学特性的影响,从热电反馈网络出发,阐述了晶体管热稳定因子S的物理意义.在考虑发射极电流正温度系数、器件能带连续性(△E_v)、重掺杂效应(△E_g)、基极和发射极加入镇流电阻(R_B和R_E)等因素的情况下。给出了功率HBT自热完全补偿(S= 0)所需最小镇流电阻(R_c)表达式.结果表明,在△E_v+△E_g>2κT时,HBT工作温度丁越大,R_c反而越小.由于R_c的减小,功率HBT将能提供更大的输出功率、功率增益和功率附加效率.更多还原

【Abstract】 In order to improve the thermal stability of RF power HBT and eliminate the self-heating effect which degenerates the transistor’s electrical characteristics,the physical significance of thermal stability factor S is presented in detail based on the thermal-electric feedback network analysis.Furthermore,the expression of the minimum ballasting resistance R_C of HBT to compensate the self-heating effect(S=0)is presented by taking into account of the temperature dependence of emitter current,the valence-band discontinuity at emit- ter junction(△E_v),the bandgap narrowing due to heavy doping(△E_g),additional ballasting resistance in emitter and base.It is found that the higher the temperature T is,the smaller the minimum ballasting resis- tance R_C to compensate the self-heating effect is under the condition that(△E_v+△E_g)>2KT.Owing to the reducing of ballasting resistance,RF power HBT will provide higher output power,power gain,and power- added efficiency(PAE)in an amplifier block.更多还原