Delta-doped β -Ga2O3 films with narrow FWHM grown by metalorganic vapor-phase epitaxy

Abstract

We report on the low-temperature metalorganic vapor-phase epitaxy (MOVPE) growth of silicon delta-doped β-Ga2O3 films with a low full width at half maximum (FWHM). The as-grown films are characterized using secondary-ion mass spectroscopy, capacitance–voltage, and Hall techniques. Secondary ion mass spectroscopy measurements show that surface segregation is the chief cause of a large FWHM in MOVPE-grown films. The surface segregation coefficient (R) is observed to reduce with reduction in the growth temperature. Films grown at 600 °C show an electron concentration of 9.7 × 1012 cm−2 and a FWHM of 3.2 nm. High resolution scanning/transmission electron microscopy of the epitaxial film did not reveal any observable degradation in the crystal quality of the delta sheet and surrounding regions. Hall measurements of the delta-doped film on the Fe-doped substrate showed a sheet charge density of 6.1 × 1012 cm−2 and a carrier mobility of 83 cm2/V s. Realization of sharp delta doping profiles in MOVPE-grown β-Ga2O3 is promising for high performance device applications.