Symrnetrlc Si/Si 1 -,Ge, two-dimensional hole gases grown by rapid thermal chemical vapor deposition

Single and symmetric double p-type modulation-doped structures have been fabricated in Si/ SiGe for the first time by rapid-thermal chemical-vapor deposition. Temperaturedependent electrical-measurements and high-field magnetotransport measurements demonstrate the presence of a well-confined two-dimensional hole gas in these samples. Nominallysymmetric normal and inverted structures differ in carrier density and mobility at most by 20%, indicating that there is little asymmetry due to surface segregation or autodoping effects. Measurements on double heterostructures confirm that the interfaces are symmetric to within 10 h;. Peak mobilities reached 2500 cm2/V s at 10 K, comparable to those obtained in similar samples grown by ultrahigh vacuum techniques.