Ruthenium: A superior compensator of InP

Abstract

The 4d-transition metal ruthenium presents a new dopant to fabricate thermally stable semi-insulating InP layers for both electron and hole injection. The layers are grown by low-pressure metalorganic chemical vapor deposition using tertiarybutylphosphine and trimethylindium as source materials for InP growth. Using bis(η5-2,4-dimethyl-pentadienyl)ruthenium(II) as precursor Ru doping concentrations of the order of 4×1018 cm−3 are achieved, determined by means of secondary ion mass spectroscopy. The Ru diffusion coefficient in InP is determined to DRu(800 °C)⩽1×10−15 cm2/s which is four orders of magnitude smaller than for Fe. Resistivities obtained under electron and hole injection are above 6×107 Ω cm and 5×108 Ω cm, respectively. In deep level transient spectroscopy measurements under electron emission and hole emission, one deep level each with concentrations around 1016 cm−3, is observed.

Development and characterisation of improved ruthenium dopant sources

“…1 and confirm the superior volatility of all of the new precursors over the conventional DMRU. In particular, ( i PrCp) 2 Ru and ( i BuCp) 2 Ru are shown to have significantly higher vapour pressures making their transport easier to maintain at high levels to allow more controllable doping to be achieved. Fig.…”

“…High speed buried heterostructure devices realised using SI current blocking layers with iron (Fe)-doped InP have invariably had a zinc (Zn)-doped p-layer adjacent to the Fe layer and it is the intermixing of Zn and Fe that significantly degrades device performance [1]. Ru has been identified as an alternative to Fe to avoid device degradation [2] as well as providing compensation of excess electrons and holes.…”

Electric characteristics of ruthenium doped InP and its application for buried‐heterostructure lasers

“…We consider the difference of resistivity is attributed to the trap level of Ru-InP. Electron trap level was shallower than the hole trap level; each value of electron and hole trap level is reported to 0.54 eV and 0.65 eV, respectively [6]. We think many trap levels exist in Ru-InP, and trap level changes under the growth condition.…”

“…Comparing (i) and (ii), the resistivity was higher when the growth temperature and pressure was lower. The resistivity measured at 1.5 V was 2×10 6 Ω cm. Comparing (ii) and (iii), the low V/III ratio leads to the high resistivity of Ru-InP.…”

Stable growth of ruthenium doped InP at the current blocking layer for buried-heterostructure lasers

“…This prevents BH-lasers from operating at high temperatures owing to the increase in the leakage current through the blocking layers. In recent years, Ru-doped InP (Ru-InP) was a focus of interest as a good semi-insulating dopant in InP [3,4]. Ru does not cause inter-diffusion with p-type dopants [5].…”