本論文主要論述一種具有步階射極結構之磷化銦鎵/砷化鎵/砷化銦鎵異質接面雙極性電晶體。關於此元件將以理論分析描述其能帶及載子分佈。相較於傳統的磷化銦鎵/砷化鎵異質接面雙極性電晶體，本元件在基－射極接面加入一層砷化銦鎵量子井，可有效提升對電洞的侷限效應。實驗的結果顯示其電流增益達220。特別是，由於採用了n型砷化鎵射極與n型砷化銦鎵量子井，可消除基－射極接面之位障尖峰，進而使集-射極之補償電壓低至70mV。因此，本研究元件極適合於線性放大器及電路應用。 In this paper, a high-performance InGaP/GaAs/InGaAs step-emitter bipolar transistor is demonstrated. For the device performances, the energy bands and carrier distributions are described by theoretical analysis. Because the confinement effect for holes is substantially enhanced by the addition of an InGaAs quantum well at base-emitter junction as compared to the conventional InGaP/GaAs heterojunction bipolar transistor, the experimental device exhibits a high current gain up to 220. In particular, a relatively low collector-emitter offset voltage of 70 mV is observed, attributed to the neglect of potential spike at base-emitter junction by the employments of an n-type GaAs emitter and an InGaAs quantum well. Consequently, the excellent performances of the studied device provide a promise for linear amplifiers and circuit applications.