Interface states in regrown GaAs p-n junctions by selective molecular beam epitaxy

Abstract

We report the first evaluation of interface states present in GaAs p-n junctions regrown on a SiO2 masked substrate by selective molecular beam epitaxy. A constant-capacitance deep-level transient spectroscopy (CC-DLTS) method is extended to the regrown p-n junction case, and a technique to distinguish the DLTS signal emerging from bulk and interface states is employed. The extracted interface state density is in good agreement with predictions based on the unified disorder-induced gap state model.

Evaluation of Deep Level Transient Spectra Originating from Continuous Distributions of Deep Energy Levels

“…where Eo is chosen so that cpT2exp(-2) = to z 1 , (7) to can be used as an adjusting parameter (see below).…”

“…where a. = x, is calculated from (14) and E, is related to T according to (7). This equation can be transformed to…”

“…The parameter to in (7) which defines the relation between temperature and energy scale does also enter the parameters ai of the series expansion of the DLTS signal, cf. (11).…”

“…But if the values of xi (which depend on the used spectrometer function and are normally fixed for a given DLTS spectrometer) are so that real zeros exist, an improvement in accuracy is expected for properly set to. One should check that to z 1 because of the usage of to as centre of expansion, and it should be taken into consideration that changes in to shift the energy scale according to (7).…”