Comparison of thermal annealing effects on electrical activation of MBE grown and ion implant Si-doped In0.53Ga0.47As

Abstract

Heavily carbon-doped In 0.53 Ga 0.47 As on InP (001) substrate grown by solid source molecular beam epitaxyThe effect of thermal annealing on the net donor concentration and diffusion of Si in In 0.53 Ga 0.47 As is compared for electrically active layers formed by ion implantation versus molecular beam epitaxy (MBE). Upon thermal treatment at temperatures of 700 C or higher for 10 min, both ion implanted and growth-doped substrates converge to a common net donor solubility. These results indicate that while MBE doped substrates typically exhibit higher active concentrations relative to implanted substrates, the higher active Si concentrations from MBE growth are metastable and susceptible to deactivation upon subsequent thermal treatments after growth. Active Si doping concentrations in MBE doped material and ion-implanted materials are shown to converge toward a fixed net donor solubility limit of 1.4 Â 10 19 cm À3 . Secondary ion mass spectroscopy of annealed samples indicates that the diffusivity of Si in MBE doped substrates is higher than those of ion implanted substrates presumably due to concentration-dependent diffusion effects.

Activation of Si implants into InAs characterized by Raman scattering

“…In the case of GaAs and In 0.53 Ga 0.47 As, previous reports indicate that the maximum active carrier concentration achievable in these materials is much higher for MBE and metal organic chemical vapor deposition (MOCVD) growth-doped substrates than implant doped substrates. 33,34 Heavy n-type doping of III-V arsenides generally results in significant concentrations of compensated carriers and prior MBE experiments report that Si doping >1 Â 10 20 was necessary to create layers with active carrier concentrations of 6 Â 10 19 cm À3 (Refs. 10 and 32) and 3.5 Â 10 20 cm À3 for an active carrier concentration of 1.2 Â 10 20 cm À3 , indicating a high concentration of electrically inactive Si.…”

Co-implantation of Al+, P+, and S+ with Si+ implants into In0.53Ga0.47As

“…The presence of vacancy defects is also likely evidenced by the highly concentration dependent nature of Si diffusion in these substrates. 25,57 Silicon is believed to diffuse via a group III vacancy mechanism in InGaAs and GaAs and a large increase in the population of group III vacancies should enhance Si diffusion in InGaAs, as is observed at high doping concentrations. Previous studies of Si diffusion in InGaAs show that at high doping concentration above 2 Â 10 19 cm À3 where electrical activation is saturated, there is a significant amount of diffusion of Si despite Si being inactive at these concentrations, suggesting the presence of a mobile, yet electrically inactive Si III -V III complex.…”

N-type Doping Strategies for InGaAs

“…This problem is exacerbated in the regrowth of 3-D structures as has been shown in Si and Ge [24,25]. While growth techniques report electrically active doping concretions of 3×10 19 cm −3 or greater, ion implantation activation saturates around 1.5×10 19 cm −3 [26].…”