Alev Kizilbulut
Cumhuriyet University, Turkey
Biography
Alev Kizilbulut is PhD student at Cumhuriyet University in Solid State Physics. She is working at ERMAKSAN Optoelectronic R&D Center as a Researcher. Her interests are the growth with MOCVD and structural, electrical and optical characterizations of semiconductor devices.
Abstract
In recent years, carbon (C) has attracted much attention for obtaining p type GaAs and AlGaAs because of its low diffusion coefficient, ability to be doped to high levels, absence of memory effect. Furthermore, it has widely used for optical and electronical devices such as vertical cavity surface emitting lasers (VCSELs), heterojunction bipolar transistors (HBTs) and edge emitting laser diode structures. High doping concentration of around ~1019-1020 cm-3 is required for ohmic contact layers. However, degradation of surface morphology also occurs at high doping concentrations and some hillocks can be seen the wafer surface. In this study, we have grown carbon p-GaAs staircase structures by using vertical type MOCVD reactor at the growth pressure of 50 mbar for obtain high doping concentration with good surfaces. Arsine (AsH3) and trimethylgallium (TMGa) were used as precursors for arsenic and gallium, respectively. Carbon tetra bromide (CBr4) was used for p-type dopant precursor. We have investigated the effect of growth temperature, V/III ratio, CBr4 flow to hole concentration of p-GaAs. Carrier concentration of p-GaAs staircase samples was performed by ECV measurements.