Energy loss rates of two-dimensional hole gases in inverted Si/Si0.8Ge0.2 heterostructures

Abstract

We have investigated the energy loss rate of hot holes as a function of carrier temperature T C in p-type inverted modulation-doped ͑MD͒ Si/SiGe heterostructures over the carrier sheet density range (3.5-13)ϫ10 11 cm Ϫ2 , at lattice temperatures of 0.34 and 1.8 K. It is found that the energy loss rate ͑ELR͒ depends significantly upon the carrier sheet density, n 2D . Such an n 2D dependence of ELR has not been observed previously in p-type SiGe MD structures. The extracted effective mass decreases as n 2D increases, which is in agreement with recent measurements on a gated inverted sample. It is shown that the energy relaxation of the two-dimensional hole gases is dominated by unscreened acoustic phonon scattering and a deformation potential of 3.0Ϯ0.4 eV is deduced.

Hot-hole effects in a dilute two-dimensional gas in SiGe

“…It determines the carriers effective temperature T e when a given power per carrier P E flows from them to the lattice at a temperature T l . The power loss P E has been studied both experimentally and theoretically for 2DES or 2DHS realized at semiconductor heterostructures or in silicon metaloxide-semiconductor field effect transistors (Si-MOSFETs) [1][2][3][4][5][6][7][8][9][10][11]. These studies have involved weakly localized carriers (at magnetic field B = 0) in the diffusive regime where the Fermi liquid description is valid, together with e-p interactions due to deformation or piezoelectric potentials, which can be screened by the 2DES.…”

“…Although the predicted power law temperature dependences of P E have been confirmed by experiments, discrepancies between the measured and calculated e-p potentials have been found in Si-MOSFETs [4][5][6] and in p-SiGe. A piezoelectric effect has been measured in spite of the covalent nature of silicon and the normally random distribution of the Ge atoms in SiGe alloys [6,10,11]. Furthermore, unexpected weak screening has been found in p-SiGe [10,11] and Si MOSFETs [4][5][6].…”

“…A piezoelectric effect has been measured in spite of the covalent nature of silicon and the normally random distribution of the Ge atoms in SiGe alloys [6,10,11]. Furthermore, unexpected weak screening has been found in p-SiGe [10,11] and Si MOSFETs [4][5][6].…”

High-frequency transport inp-typeSi∕Si0.87Ge0.13heterostructures studied with surface acoustic w

“…13,14,15 However, it is valuable to investigate the energy-loss mechanisms in these structures using a contactless method (such as possible here using acoustics) that excludes carrier injection to the lowdimensional interface from contact areas. Hole heating may be described by means of a carrier temperature T c , greater than the lattice temperature T .…”

Two-Dimensional Analytical Threshold Voltage Modelling of Pseudomorphic Si0.8Ge0.2p-Channel MOSFETs

“…hole effective mass m * = 0.23m0 [23] depleted background impurities N dep = 5×10 16 cm −2 [6,18] substrate doping N d = 1×10 15 cm −3 [6,18] built in voltage…”