We report on the formation of p+ layers in GaAs by the co-implantation of indium with carbon. Sheet hole concentrations of 2E14 cm−2 were achieved. The co-implant acts to create stoichiometric disturbances and to increase VAs concentration, allowing the C to occupy the vacant As lattice sites. The effect of In on the stoichiometry of the implanted layer was investigated. It was found that addition of 0.1–1% of a group III ion had the effect of shifting the effective As fraction toward the Ga-rich region, thus altering the crystal stoichiometry.

Damage accumulation in Si-implanted GaAs has been characterized by ion channeling and Raman scattering as a function of implant temperature, dose, and dose rate. The damage was found to be extremely sensitive to temperature near room temperature (RT), such that an implant dose of 6×1014Si/cm2 which produced a peak damage fraction of 94% at 20°C gave only a 15% damage fraction at 30°C. Such a sharp damage transition obviously has important implications for controlling the activation of dopants implanted at RT. One consequence is a strong dependence of the damage on dose rate near RT: the damage increases with dose rate as the dose rate is increased over nearly two orders of magnitude. Comparison of Ion channeling results with Raman scattering measurements indicates that the morphologies of the dose-rafe-dependent and dose-dependent damage components in RT implants are distinct, ie‥ the rate-dependent component primarily consists of crystalline defects, while the dose-dependent damage nas a large amorphous contribution. These experimental observations are discussed in terms of the competition between different damage nucleation and growth mechanisms as a function of the implant parameters.

High-energy (3 MeV) Si implantations were performed in InP:Fe at an elevated temperature of 200 °C for fluences 8×1014, 2×1015, and 5×1015 cm“2. For the 8×1014 cm−2 fluence, an activation of 82 %, carrier mobility of 1200 cm2/V-s, a peak carrier concentration of 9×1018 cm−3, and lattice quality comparable to that of virgin crystal were obtained. No amorphization takes place for any of the fluences used. Boron compensation implantations were performed in InP:Sn (n sime 2×1018 cm3) at room temperature in the energy range 1 to 5 MeV and fluence range 1011 to 1015 cm−2. After heat treatment, maximum resistivity of the order of 106 Ω-cm was obtained in B implanted InP.

The chemical profiles of Zn, Ge, and Se implanted into InP at elevated temperatures have been measured with secondary ion mass spectrometry and correlated to the implantation damage as deduced from RBS/channeling measurements. An asymmetric broadening of the chemical profiles towards the bulk was found for implantation temperatures above 150°C. This effect is concluded to be due to impurity channeling during implantation.

The lattice location of ion implanted Ga, Ge, and Se in InP has been determined with a combined RBS/channeling-PIXE technique and correlated to the carrier concentration and mobility profiles obtained with differential Hall/resistivity measurements.

Oxygen ion-implantation can be used to create high resistivity regions in GaAs and InP. We have studied the low dose oxygen implantation in GaAs and InP by photoreflectance spectroscopy (PR), deep level transient spectroscopy (DLTS) and current-voltage (I-V) characteristics. Rapid thermal annealing (RTA) treatments were carried out at different temperatures after implantation to study the annealing temperature effect. The surface disturbance by implantation was studied by PR. Free carrier compensation was observed in every implanted sample and gave improved I-V properties. By DLTS tests, one electron trap with Ea = Ec-0.15eV and a hole trap with Ea = Ev + 0.76eV in the starting GaAs wafer disappeared after O+ implantation due to carrier compensation. In undoped InP, three new electron traps with Ea = Ec-0.47eV, 0.28eV and O.lleV were created after O+ implantation which are believed to be damage related. The comparison of the results from undoped and n-type doped InP indicated that the carrier compensation effect is substrate doping dependent.

Production of midgap electron traps in rapid-thermal-processed (RTP) GaAs with sio2 encapsulant has been studied by deep-level transient spec-troscopy in connection with the rapid out-diffusion of Ga through Sio2. Sio2 films of 50 and 1250 nm in thickness have been deposited on LEC n-type (100) GaAs doped with Si. RTP has been performed at 760 and 910°C for 9 s. The broadened DLTS signal consists of four electron traps with the energy levels of Ec - 0.79, 0.83, 0.78 and 0.81 eV. The depth profiles of the total concentration of four traps coincide with those of the decreased carrier concentration multiplied by 0.14 and 0.054 with RTP at 910 and 760°C for 50-nm-thick samples, respectively. These are 0.29 and 0.026 for 1250-nm-thick samples. This means that the origin of these traps is the Ga vacancy formed by the out-diffusion of Ga since the decrease of the carrier concentration by RTP has been ascribed to the formation of VGa-SiGa complex. However, the observation of the persistent photocapacitance quenching effect indicates that these traps are correlated with the As antisite formed by the migration of As into the Ga vacancy. Four kinds of complex defects including the As antisite are produced by RTP which are complex defects of EL2 group.

The effects of high temperature isothermal annealing on the electrical properties of donor and acceptor defects in n-type LEC GaAs are investigated. The annealing experiments are performed under As-rich atmosphere at 1000°C for 1–4 and 16 hours followed by a very quick quenching into cold water of the quartz ampoules containing the samples. The donor and acceptor levels are detected respectively by standard (DLTS) and optical (ODLTS) deep level spectroscopy. DLTS results show the presence of one single donor level present in unannealed and annealed samples at Ec - 0.79eV which is identified as the well known electron trap EL2 Only the sample annealed for 16 hs exhibits the presence of a new electron trap named TAI at Ec - 0.32eV. The appearance of TAI is correlated in one hand with the evolution of EL2 concentration and in the other hand to the effect of long duration (16 hs) of the treatment. For acceptor levels, two hole traps HT1 and HT2 are detected respectively at EV + 0.18 eV and EV+ 0.28 eV. HT1 is detected only in samples annealed for 4 and 16 hs and HT2 is detected in all studied samples. Photoluminescence (PL) measurements show the presence of the 1.44 eV band corresponding to gallium antisite GaAs defect. This band observed in unannealed and annealed samples shows that GaAs remains stable even after thermal annealing at lOOO°C for 16 hs and it is correlated with the presence of HT2.

The effect of planar Si doping on the DX center in AlGaAs is investigated using Capacitance-Voltage and Deep Level Transient Spectroscopy techniques. We observe an increase of approximately six orders of magnitude in the DX center capture cross section in Al.26Ga.74As with planar doped Si spikes of 2×1012cm−2 as compared to conventional homogeneous Si doped Al.26Ga.74As. We also observe a small increase in the DX activation energy which was initiated at a lower planar doping of 4×1011 cm−2 and remained constant for the higher planar doping case. We believe the DX center concentration is not changed by the planar doping levels studied here. A model is proposed to explain the increase in capture cross section based on a biaxial stress state in the planar doped AlGaAs region.

The influence of oxygen-related defects on the compensation behavior of semi-insulating gallium arsenide has been studied. Off-center substitutional oxygen (Ga-O-Ga center) forms an electrically active defect with two levels in the fundamental gap. The negative-U ordering of these levels is the origin for very unusual electrical and optical properties. By oxygen implantation and annealing high concentrations of this center are created which are technologically useful to obtain high-resistivity surface layers.

We report the the first demonstration of optically bistable switching in monolithic opto-electronic transistor configuration using all III-V components. A strained InGaAs/GaAs asymmetric Fabry-Perot (ASFP) modulator / detector, a strained resonant tunneling diode (RTD), and a GaAs based field-effect-transistor (FET) were used in this demonstration.

Indium phosphide (InP) and its related alloys have gained increased importance in recent years due to their widespread application in opto-electronics and high speed microelectronics. Ion beam processing has been used to produce electrical activity in selective areas of wafers and for device isolation. However, major problems remain concerning the location, electrical/chemical activity, and thermal stability of the implanted atoms in such devices. In this paper, we present detailed results concerning the distribution of 1H and Be atoms implanted into single crystal InP wafers. Secondary ion mass spectrometry has been used to depth profile 1H and Be implanted at different engergies, from 0.1 to 1.0 MeV, and with fluences up to 1016 cm2. Implanted samples have also been examined after furnace annealing to determine the onset and extent of thermal redistribution. Resulting profiles have been compared with corresponding implants into single crystal GaAs to help clarify diffusion behavior.

This review emphasizes controlled shallow doping of GaAs by ion implantation for state-of-art GaAs IC technology. Electrical activation behavior of Si+ and SiF+ implanted GaAs after RTA under capless and PECVD Si3N4-capped conditions will be compared. It will be demonstrated that a remarkable improvement (> 20 %) both in carrier activation and as well mobility can be achieved by co-implanting low doses (< 1013 cm−2 of Al+ into n-dopant (including Si, Se and Te) implanted GaAs and subsequently annealing the material under capless RTA conditions. The maximum improvement in the electrical results with Al+ co-implants occurs for doses (e.g. < 1013 cm−2 for 30 keV Si+) which are used for fabricating shallow channels for submicron GaAs MESFETs. Complex dopant-annealing environment interactions during a buried p layer formation (using either Mg+ or Be+) will be discussed.