Wafer Characterization

1. Final polishing is done by 0.05µm Al₂O₃ or SiO₂ suspension. Additional polishing, etching and cleaning before next processes are permitted.
2. At the instance of customer the wafer size can be varied.

Extremely low doped GaAs P-i-N layer grown in a single LPE growth process

The structure is based on a GaAs P-i-N layer with a wide near-fully compensated (intrinsic) i-region, which is grown by improved Liquid Phase Epitaxy (LPE) in a single growth process (Fig.1).

The main feature of these layers is the wide range of doping concentration in P and N components of a layer (from 10¹⁵cm^-3 up to less than 10¹²cm^-3 in the N-part of a layer and from less than 10¹²cm^-3 up to 10¹⁷cm^-3 in the P-part of a layer, Fig. 2 and 3).

Similar properties have p-i-n layers grown on surfaces of the heavy-doped P or N - type or semi-isolating GaAs (111)B substrates. Also it's looked promising the growing by this method of low-doped GaAs or AlGaAs layers on substrates from other materials: semi-conductors, including Si , Ge, and isolators, including diamond, sapphire, etc.

Milestone of GaAs Wafers Process

Such extremely low net concentration and several tens micrometers of i-region width provide the breakdown voltage up to 1000 Volt and more.
Side benefits of this structure are low leakage current up to 300°C of junction temperature, small capacitance, high radiation hardness.

Comparison of the reverse characteristics of Si and GaAs power diodes at high temperature.

The unique properties of the structure can be used for the design of high-performance, high-voltage GaAs power devices with homo and heterojunctions (diodes, rectifiers, transistors, phototransistor etc.) that provide higher efficiency, higher current density, higher frequency, higher operation speed, higher operation temperature etc.

Further these structures are very promising for development of the high-efficiency radiation (nuclear and gamma) detectors and thermo-sensors.

On the other hand these structures create prospects of wider use of GaAs in planar technology. In particular, creation MOSFETs as n and p-type on their basis looks promising. n or p-type depends on type of conductivity of a used part (n, n_i, p_i or p) of a p-i-n layer (see Fig.3).

Novelty is the opportunity of manufacturing MOSFETs on the GaAs layers with essential lower than 10¹⁵ cm^-3 levels of doping concentration (Fig.3). This assumes to enhance channel transport as well as to reduce power dissipation.

Offered p-i-n structure it will be possible effective also at creation on its basis CMOS, MMIC, solar sells and etc.

Cassette Loading	Pilot LPE system	Etching & Cleaning
LPE growing		Layer Testing

Wafer fabrication

Next:Diodes and Rectifiers