Investigation of InP/InGaAs PNP Heterojunction Bipolar Transistors
| Autor: | Yu-Chi Kang, 康育綺 |
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| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 In this thesis, two heterojunction bipolar transistors (HBTs), were grown by low-pressure metal organic chemical vapor deposition (LP-MOCVD), have been fabricated and investigated. First, by theoretical analysis and experiment results the DC performances of InP/InGaAs PNP δ-doped HBT are investigated. The insertion of a δ-doped sheet and two spacer layers at the emitter-base (E–B) junction can efficiently eliminate the potential spike at E-B junction and reduce the offset voltage. Excellently DC performances include a maximum current gain of 50 and a low offset voltage of 70 mV. The ideality factor nc of collector current and the ideality factor nb of base current are nearly equal to unity at low current levels. This means that the thermionic-emission and diffusion mechanisms dominate the hole transportation across the E-B junction and the addition of the δ-doped sheet and two spacer layers only slightly increase the base recombination current. On the other hand, an InP/InGaAs PNP heterostructure-emitter bipolar transistor (HEBT) is investigated by the theoretical analysis and experiment results. To utilize a thin p+-InGaAs emitter layer between emitter and base, the potential spike at InP/InGaAs heterojunction is also completely removed. The excellent DC performances are demonstrated include a maximum current gain of 88 and a low offset voltage of 54 mV. At low current levels, the ideality factor nc of collector current is 1.05 and ideality factor nb of base current is 1.2. It mean that the thermionic-emission and diffusion mechanisms dominate the hole transportation across the E-B junction and the addition of a thin p+-InGaAs emitter layer does not increase the base recombination current excessively and degrade the device performance. In this thesis, the potential spike at InP/InGaAs heterojunction of InP/InGaAs PNP δ-doped HBT and InP/InGaAs PNP HEBT are efficiently eliminated, no matter insertion of the δ-doped sheet and two spacer layers or a thin p+-InGaAs emitter layer at the E–B junction. Thus, the excellent DC performances including higher current gain, lower offset voltage and high device linearity could be used signal and low power consumption integrated circuit applications. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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