A.W. Nelson

The role of MOVPE in the manufacture of high performance InP based optoelectronic devices

Abstract This paper describes, for the first time, the development of atmospheric pressure MOVPE growth for the large scale production of InP based opto-electronic devices. Results are presented on material quality, large area uniformity, device performance, yield and reliability, both in an R&D environment and in the production facility to demonstrate that InP based MOVPE technology has now made the crucial transition from the research and development area into large scale production.

Anomalous behaviour of dopants in atmospheric pressure MOVPE of InP

The doping level of p-type InP doped with Zn or Cd, incorporated into various structures, has been investigated as a function of the gaseous ambient to which the structure is exposed during cooling from typical MOVPE growth temperatures. It is found that the doping level is strongly dependent on this ambient. If AsH3 is present the doping level is lower by up to an order of magnitude than if PH3 is used, which in turn gives a doping level lower by up to a factor of two than H2 alone. Both MOVPE grown epilayers and Czochralski grown bulk crystals have been studied and found to behave similarly. SIMS experiments show that this is due to electrical deactivation rather than loss of the dopant species itself. n-Type InP and n- or p-type GaAs do not appear to be affected. Significant quantities of atomic H are found in samples exposed to the hydrides during cooling, consistent with their pyrolysis being catalysed by the semiconductor surface. The anomalous doping level phenomena are discussed in terms of a model involving deactivation of the dopant by complex formation with H, as observed by Johnson et al. in GaAs exposed to a hydrogen plasma.

High Reliability Planar InGaAs/InP Photodiodes Made With High Yield by Atmospheric Pressure MOVPE

A high-yield process for making planar InGaAs/InP photodiodes based on metal-organic vapour phase epitaxy (MOVPE) growth at atmospheric pressure has been developed. The process results in very good uniformity and yield and gives high-performance devices of excellent reliability, with a random failure rate of less than 0.3 FITs at 20°C. This reliability performance is easily able to meet the stringent requirements for detectors in submarine systems.