Abstract:
A process for the production of a semiconducting catenated phosphorus film characterised in that it comprises sputtering a thin film thereof onto a substrate is disclosed. The present process may be applied to the production of semiconductor devices. Referring to the accompanying illustrative drawing, a sputtered film 22 may be used in a sandwich configuration on a glass substrate 24 with a metallic lock contact 26 and metal dot top contacts 28. For example, amorphous and polycrystalline films of KP 15 may be formed by RF diode sputtering targets of KP 15 and excess phosphorus in an argon phase. Substrate temperatures up to 280-300°C provide amorphous films. Higher temperatures provide microcrystalline or polycristalline films. These films have high resistance and may be used as the insulator in MIS devices employing III-V semiconductors. Co-sputtering with nickel increases the conductivity of the films from approximately 10 -10 (ohm-cm)- 1 to 10- 2 (ohm-cm) -1 ; only reduces the optical gap by 0.2 eV; and reduces the activation energy from 0.8 eV to 0.2 eV; the nickel content varying from 5-15%. Substrates include glass, silicon, tantalum, stainless steel, gallium phosphide and gallium arsenide, and glass metallized with metals, such as titanium, nickel and aluminium. Double diode electrical characteristics have been observed in devices formed on metallized glass substrates having co-sput- . terred thereon thin film polyphosphides and nickel with nickel and titanium top contacts. The present invention represents an advance over the prior art.
Abstract:
A thin film transistor characterised in that it comprises, as a switched semiconductor portion thereof, a thin film comprising MP x wherein M represents at least one alkali metal; P represents at least one pnictide; and x ranges from 15 to infinity is disclosed. A process for the production of a transistor characterised in that it comprises vacuum plasma sputtering of successive layers in contact of a semiconductor comprising MP x , wherein M represents at least one alkali metal; P represents at least one pnictide; and x ranges from 15 to infinity; and an insulating layer comprising a pnictide is also disclosed. An insulated semidconductor device characterised in that it comprises as the switched semiconductor portion thereof a layer comprising MP., wherein M represents at least one alkali metal; P represents at least one pnictide; and x ranges from 15 to infinity; and an insulating layer comprising a pnictide is further disclosed. Referring to the accompanying illustrative diagram, a Schottlky barrier thin film field effect transistor in accordance with the present invention may comprise a glass substrate (20), a high pnictide polypnictide semiconductor (22) of high resistivity, a metal (approximately 1 % Ni) doped layer (24) of the same semiconductor material of lower resistivity and metal source (26), gate (28) and drain (30) contacts deposited on layer (24). The present invention provides advances over the prior art.
Abstract:
A thin film transistor characterised in that it comprises, as a switched semiconductor portion thereof, a thin film comprising MP x wherein M represents at least one alkali metal; P represents at least one pnictide; and x ranges from 15 to infinity is disclosed. A process for the production of a transistor characterised in that it comprises vacuum plasma sputtering of successive layers in contact of a semiconductor comprising MP x , wherein M represents at least one alkali metal; P represents at least one pnictide; and x ranges from 15 to infinity; and an insulating layer comprising a pnictide is also disclosed. An insulated semidconductor device characterised in that it comprises as the switched semiconductor portion thereof a layer comprising MP., wherein M represents at least one alkali metal; P represents at least one pnictide; and x ranges from 15 to infinity; and an insulating layer comprising a pnictide is further disclosed. Referring to the accompanying illustrative diagram, a Schottlky barrier thin film field effect transistor in accordance with the present invention may comprise a glass substrate (20), a high pnictide polypnictide semiconductor (22) of high resistivity, a metal (approximately 1 % Ni) doped layer (24) of the same semiconductor material of lower resistivity and metal source (26), gate (28) and drain (30) contacts deposited on layer (24). The present invention provides advances over the prior art.
Abstract:
Pnictide thin films, particularly phosphorus, grown on III-V semiconductors, particularly InP, Gap, and GaAs, are amorphous and have a novel layer-like, puckered sheet-like local order. The thin films are typically 400 Angstroms (4 x 10⁶cms) thick and grown preferably by molecular beam deposition, although other processes, such as vacuum evaporation, sputtering, chemical vapour deposition and deposition from a liquid melt, may be used. The layers are grown on the (100) (110) and (111) surfaces of the III-V crystals. The pnictide layer reduces the density of surface states, and allows the depletion layer to be modulated, the surface barrier reduced, the electron concentration at the surface increased, and there is a decrease in the surface recombination velocity and an increase in the photoluminescence intensity. The layers may be utilized in MIS and metal-semiconductor (Schottky) devices, for example, to insulate and passivate MISFETS, to passivate MESFETS, to reduce the surface current component of the reverse bias dark current in P-I-N and avalanche diodes, and to improve performance of opto-electronic devices, such as light-emitting diodes, lasers, solar cells, photo-cathodes and photo-detectors. The pnictide layer may be applied to intermetallic and compound semiconductors having a pnictide component. The pnictides may be phosphorus, arsenic, antimony or bismuth, or combinations thereof.
Abstract:
A process for the production of a semiconducting catenated phosphorus film characterised in that it comprises sputtering a thin film thereof onto a substrate is disclosed. The present process may be applied to the production of semiconductor devices. Referring to the accompanying illustrative drawing, a sputtered film 22 may be used in a sandwich configuration on a glass substrate 24 with a metallic lock contact 26 and metal dot top contacts 28. For example, amorphous and polycrystalline films of KP 15 may be formed by RF diode sputtering targets of KP 15 and excess phosphorus in an argon phase. Substrate temperatures up to 280-300°C provide amorphous films. Higher temperatures provide microcrystalline or polycristalline films. These films have high resistance and may be used as the insulator in MIS devices employing III-V semiconductors. Co-sputtering with nickel increases the conductivity of the films from approximately 10 -10 (ohm-cm)- 1 to 10- 2 (ohm-cm) -1 ; only reduces the optical gap by 0.2 eV; and reduces the activation energy from 0.8 eV to 0.2 eV; the nickel content varying from 5-15%. Substrates include glass, silicon, tantalum, stainless steel, gallium phosphide and gallium arsenide, and glass metallized with metals, such as titanium, nickel and aluminium. Double diode electrical characteristics have been observed in devices formed on metallized glass substrates having co-sput- . terred thereon thin film polyphosphides and nickel with nickel and titanium top contacts. The present invention represents an advance over the prior art.