Monolithic integrated device of PIN diode and field effect transistor and method of manufacturing the same

Die Erfindung betrifft eine integrierte Anordnung einer lateralen PIN-Diode und eines HFET oder MESFET. Die Schichtenfolge des Feldeffekttransistors besitzt eine derart geringe Schichtdicke, daß PIN-Diode und Feldeffekttransistor quasi planar angeordnet sind. Die FET-Schichtenfolge enthält eine LTG-Schicht, so daß Backgating- und Kurzkanaleffekte reduziert und das Hochfrequenzverhalten verbessert wird. A novel monolithically integrated arrangement of a PIN diode and a FET has (a) a PIN diode formed of an undoped epitaxially produced semiconductor layer with implanted n- and p-contact regions; (b) a FET consisting of a semiconductor layer sequence with a total thickness of less than 0.2 microns; (c) the FET arranged laterally to the PIN diode with an etch-stop layer, on which the FET is applied, provided on the PIN diode semiconductor layer in the region of the FET; and (d) a quasi-planar arrangement of the PIN diode and the FET due to the low total thickness of the FET structure. Also claimed is a process for prodn. of a layer sequence for the above arrangement by (i) carrying out a first epitaxial process to produce, on a semi-insulating GaAs substrate (1), a 0.2 microns thick buffer layer (2) of undoped GaAs and an AlGaAs/GaAs superlattice, a 0.4-0.8 mu m thick undoped GaAs layer (3), a 5-50 nm. thick undoped AlAs or AlGaAs etch-stop layer (4) and a 50 nm. thick GaAs passivation layer, applying and structuring a dielectric layer to form an implantation mask for implantation of n- and p-contact regions (7, 8) for the PIN diode in the undoped GaAs layer (3), healing the implanted region, removing the dielectric layer and then removing the passivation layer by thermal desorption under As pressure or by selective etching with AsBr3 or AsCl3; and (ii) carrying out a second epitaxial process to produce a regrowth layer sequence of a 10-100 nm. thick undoped low temp. grown (LTG) GaAs layer (9), a 5-20 nm. thick undoped AlAs, AlGaAs or GaInP diffusion barrier layer (10), a HFET or MESFET layer sequence (11) of max. 0.2 mu m total thickness and a 40 nm. thick n-doped GaAs cover layer (12) with a doping concn. of 5 x 10 cm..