Ultrahigh room-temperature hole Hall and effective mobility in Si0.3Ge0.7/Ge/Si0.3Ge0.7 heterostructures

Abstract

We have obtained ultrahigh room-temperature (RT) hole Hall and effective mobility in Si0.3Ge0.7/Ge/Si0.3Ge0.7 heterostructures with very small parallel conduction. Reducing parallel conduction was achieved by employing Sb doping in Si0.3Ge0.7 buffer layers, which drastically increased RT hole Hall mobility up to 2100 cm2/V s in the strained Ge channel modulation-doped structures and improved device characteristics of the p-type metal–oxide–semiconductor field-effect transistors with the strained Ge channel. The peak effective mobility reached to 2700 cm2/V s at RT, which was much higher than the bulk Ge drift mobility.

Hole density dependence of effective mass, mobility and transport time in strained Ge channel modulation-doped heterostructures

“…By utilizing this ultrahigh mobility structure, the strained Ge channel MOSFET with the effective hole mobility of 2700 cm 2 /V s at room temperature was demonstrated recently. 4 The basic transport properties of two-dimensional hole gas ͑2DHG͒ in the strained Ge channel, however, have not been systematically studied so far. Not only the carrier density dependence of the effective hole mass but also that of the mobility itself has not been well investigated yet.…”

Self-consistent solution of Schrödinger–Poisson equations in a reverse biased nano-scale $$p$$ p - $$n$$ n junction based on $$\hbox {Si/Si}_{0.4}\hbox {Ge}_{0.6}/\hbox {Si}$$ Si/Si 0.4 Ge 0.6 / Si quantum well

“…Triangular barrier is the (x)) has to be subtracted from the bandgap energy (E g (x)) in Eqs. (17) and (18). The hole generation rate due to tunneling (G T h (x)) have the same form that of tunneling induced electrons generation rate (i.e.…”

“…The Si/Si 1−x Ge x heterostructures (where x is the mole fraction of Ge in Si 1−x Ge x ) has added a rich variety of applications in Si monotonic technology. Especially the Si/Si 1−x Ge x /Si quantum wells can be used to realize various novel electronic devices such as high-speed heterojunction bipolar transistors, high-speed field effect transistors, modulation doped field effect transistors, resonant tunneling diodes, [14][15][16][17][18][19][20][21][22][23][24][25][26] etc. The said structure is also very useful to realize various high performance optoelectronic devices such as light emitting diodes (LEDs) [27], MOS LEDs [28], p-i-n photodetectors [29], phototransistors [30,31], etc.…”

Fabrication of Ge channels with extremely high compressive strain and their magnetotransport properties

“…The compressive strain, which is induced by lattice mismatch between Ge and relaxed SiGe, is known to reduce the hole effective mass [1] and consequently increase the hole mobility. So far, very high hole mobilities have been reported in strained Ge channels, most of which were fabricated on SiGe buffer layers with Ge concentrations of 60-70% [2][3][4][5][6][7][8][9][10]. There are still few reports [11][12][13] on the transport property of Ge channels with much larger strain, and consequently the strain dependence of the effective mass has not been investigated.…”