Heterojunction bipolar transistors with SiGe base grown by molecular beam epitaxy

Suppression of boron transient enhanced diffusion in SiGe heterojunction bipolar transistors by carbon incorporation

“…This outdiffusion causes the formation of conduction-band barriers at the emitter-base and base-collector interfaces, which reduce the transistor's gain, early voltage, and frequency performance. [2][3][4][5] To accommodate any boron movement during postgrowth processing, undoped SiGe spacer layers are grown on either side of the doped SiGe base. 3 However, the thickness of these undoped spacer layers is limited by the critical thickness of the SiGe strained film.…”

“…Boron outdiffusion may be caused by ͑1͒ thermal annealing, 3 ͑2͒ transient enhanced diffusion effects due to an arsenic emitter implantation and anneal, 2 or ͑3͒ TED due to an extrinsic boron implantation and anneal. 6 We have found that the addition of carbon to the base of SiGe HBTs sharply reduces boron outdiffusion and improves collector electrical characteristics in all cases.…”

Comparison of Mesa- Etched and Ion- Implanted GexSi1-x Heterojunction Bipolar Transistors

“…20 Si 0 . 80 metastable strained layer at 850 C for 10 min [3]. Indeed, Sturm et al were able to raise the wafer temperature to 850 C after growth of a 50 nm Ge.…”

“…Base current ideality factors close to one have been reported for devices fabricated by UHV/ CVD [1], limited reaction processing [2], and molecular beam epitaxy [3]. However, many other researchers have reported transistors with chararacteristics strongly influenced by defects of various types.…”

Evidence of Ge island formation during thermal annealing of SiGe alloys: Combined atomic force microscopy and Auger electron spectroscopy study

“…[1][2][3] Two important issues are of concern for further use of these structures in Si technology: the growth of pseudomorphic strained SiGe layers and their compatibility with subsequent processing steps. [1][2][3] Two important issues are of concern for further use of these structures in Si technology: the growth of pseudomorphic strained SiGe layers and their compatibility with subsequent processing steps.…”