A low-complexity 62-GHz fT SiGe heterojunction bipolar transistor process using differential epitaxy and in situ phosphorus-doped poly-Si emitter at very low thermal budget
“…The P atoms cannot be cleared by hydrogen; this can be explained by the formation of stable P complexes on the surface. By changing parameters such as temperature, pressure, purge time would be helpful [ 24 , 40 ], but too long purge time is not suitable due to time cost, and high temperature (> 950 °C) causes Si-Ge interdiffusion [ 41 ]. Fig.…”
Vertical gate-all-around field-effect transistors (vGAAFETs) are considered as the potential candidates to replace FinFETs for advanced integrated circuit manufacturing technology at/beyond 3-nm technology node. A multilayer (ML) of Si/SiGe/Si is commonly grown and processed to form vertical transistors. In this work, the P-incorporation in Si/SiGe/Si and vertical etching of these MLs followed by selective etching SiGe in lateral direction to form structures for vGAAFET have been studied. Several strategies were proposed for the epitaxy such as hydrogen purging to deplete the access of P atoms on Si surface, and/or inserting a Si or Si0.93Ge0.07 spacers on both sides of P-doped Si layers, and substituting SiH4 by SiH2Cl2 (DCS). Experimental results showed that the segregation and auto-doping could also be relieved by adding 7% Ge to P-doped Si. The structure had good lattice quality and almost had no strain relaxation. The selective etching between P-doped Si (or P-doped Si0.93Ge0.07) and SiGe was also discussed by using wet and dry etching. The performance and selectivity of different etching methods were also compared. This paper provides knowledge of how to deal with the challenges or difficulties of epitaxy and etching of n-type layers in vertical GAAFETs structure.
“…The P atoms cannot be cleared by hydrogen; this can be explained by the formation of stable P complexes on the surface. By changing parameters such as temperature, pressure, purge time would be helpful [ 24 , 40 ], but too long purge time is not suitable due to time cost, and high temperature (> 950 °C) causes Si-Ge interdiffusion [ 41 ]. Fig.…”
Vertical gate-all-around field-effect transistors (vGAAFETs) are considered as the potential candidates to replace FinFETs for advanced integrated circuit manufacturing technology at/beyond 3-nm technology node. A multilayer (ML) of Si/SiGe/Si is commonly grown and processed to form vertical transistors. In this work, the P-incorporation in Si/SiGe/Si and vertical etching of these MLs followed by selective etching SiGe in lateral direction to form structures for vGAAFET have been studied. Several strategies were proposed for the epitaxy such as hydrogen purging to deplete the access of P atoms on Si surface, and/or inserting a Si or Si0.93Ge0.07 spacers on both sides of P-doped Si layers, and substituting SiH4 by SiH2Cl2 (DCS). Experimental results showed that the segregation and auto-doping could also be relieved by adding 7% Ge to P-doped Si. The structure had good lattice quality and almost had no strain relaxation. The selective etching between P-doped Si (or P-doped Si0.93Ge0.07) and SiGe was also discussed by using wet and dry etching. The performance and selectivity of different etching methods were also compared. This paper provides knowledge of how to deal with the challenges or difficulties of epitaxy and etching of n-type layers in vertical GAAFETs structure.
“…The Si/Ge heterojunction bipolar transistor process using differential epitaxy and in situ phosphorus-doped poly-Si emitter [14] at very low thermal budget is designed.…”
<strong>Innovation of Heterojunction Bipolar Transistor (HBT) technology is a major game changer in wireless communication, power amplifiers and other major fields of electronics. HBTs play a vital role in extending the advantages of silicon bipolar transistors to significantly higher levels. Research on HBT is focused on reducing cost and improving reliability. These transistors have a wide range of applications namely, digital-to-analog converters, logarithmic amplifiers, RF chip sets for CDMA wireless communication systems, and power amplifiers for cellular communications. Our study focuses on utilizing the high mobility of pure Ge instead of often-used graded Ge base. Non-grtaded Ge base enhanses carrier transport which in turn increases the gain and cut-off frequency of the HBT. We have developed a high frequency, high current gain, high power gain and less noisy heterojunction bipolar transistor operating above 100GHz frequency. Lattice mismatch at emitter and collector junctions is compensated by inserting SiGe buffer layers. ATLAS TCAD - SILVACO software is used for modelling of this novel device.</strong>
“…SiGe alloys have been used in many electronic devices, such as stressor and high mobility channel materials, for years. Both Ge or SiGe layers could be grown selectively in trenches or around SiNWs as core layer (Grahn et al, 2000;Hållstedt et al, 2008b;Radamson and Kolahdouz, 2015). The interface between core and shell reduces thermal conductivity by phonon scattering.…”
In our environment, the large availability of wasted heat has motivated the search for methods to harvest heat. As a reliable way to supply energy, SiGe has been used for thermoelectric generators (TEGs) in space missions for decades. Recently, micro-thermoelectric generators (μTEG) have been shown to be a promising way to supply energy for the Internet of Things (IoT) by using daily waste heat. Combining the predominant CMOS compatibility with high electric conductivity and low thermal conductivity performance, Si nanowire and SiGe nanowire have been a candidate for μTEG. This review gives a comprehensive introduction of the Si, SiGe nanowires, and their possibility for μTEG. The basic thermoelectric principles, materials, structures, fabrication, measurements, and applications are discussed in depth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
