Precision voltage reference

Claim 2

A precision voltage reference, characterized by : a) a host semi-insulating substrate (31); b) a first layer (32) of doped semiconductor material forming an ohmic contact, on said host semi-insulating substrate; c) a superlattice structure (12, 34) comprising a double barrier system having a layer (18) of smaller band-gap material sandwiched between two layers (24, 22) of larger band-gap material, on said first layer (32) of doped semiconductor material; and d) a second layer (28) of doped semiconductor material forming an ohmic contact on said superlattice structure.

Claim 3

The device of claim 1, characterized in that said structure is grown by an epitaxial method.

Claim 4

The device of claim 2, characterized in that said epitaxial method is molecular beam epitaxy (MBE).

Claim 5

The device of claim 2, characterized in that said epitaxial method is metal organic chemical vapor deposition (MOCVD).

Claim 7

The device of claim 5, characterized in that said superlattice structure (12) comprises a quantum well (18).

Claim 8

The device of claim 6, characterized in that said superlattice structure (12) is a resonant tunneling diode.

Claim 9

The device of claim 7, characterized by a superlattice neutral region layer (26) placed between said first layer (32) of doped semiconductor material and said superlattice structure (34).

Claim 11

The device of claim 9, characterized in that the width of the quantum well (18) is small enough so as to cause formation of at least one discrete energy level within the quantum well, above the conduction band energy of the second layer (28) of doped semiconductor material which is a cathode.

Claim 13

The device of claim 11, characterized in that said superlattice neutral region (26) is Al y Ga 1-y As.

Claim 17

Support electronic means for tracking the resonant peak current of a superlattice structure according to one of the preceding claims and for providing a precision voltage reference output based on the tracking of the current, characterized by: a) a current monitor (58) connected to the ohmic contacts (34, 36) of said first (32) and second (28) layers of doped semiconductor material; b) a first amplifier (66) connected to said current monitor; c) an integrator (54) connected to said current monitor; d) a phase detector (50) connected to said first amplifier (66) and to said integrator (54); e) an oscillator (40) connected to said phase detector (50); f) a second amplifier (78) connected to said ohmic contacts (34, 36) of said first (32) and second (28) layers of doped semiconductor material (Fig. 6).

Claim 18

Support electronics according to claim 16, charac­terized in that said second amplifier (46) is an integrator (78) comprising at least one feedback resistor (84, 82) having a plurality of materials of different temperature coefficients.

Claim 19

A precision voltage reference, characterized by: a) a first superlattice resonant tunneling diode (10) having a peak current flow at a specific voltage; b) a second superlattice resonant tunneling diode (11) having a peak current flow at a specific voltage; and c) support electronics means (42, 44, 46), connected to said first and second resonant tunneling diodes, for tracking the peak current flows of said first and second resonant tunneling diodes and for providing a precision voltage reference output (48), wherein d) each of said first and second tunneling diodes comprises a structure according to one of the claims 1 to 15.

Claim 20

Electronics for a device according to claim 18, characterized by: a) a first current monitor (58) connected to said first resonant tunneling diode (10); b) a first amplifier (66) connected to said first current monitor (58); c) a first phase detector (50) connected to said first amplifier (66); d) a first integrator (54) connected to said first phase detector (50) and to said first current monitor (58); e) a second current monitor (60) connected to said second resonant tunneling diode (11); f) a second amplifier (68) connected to said second current monitor (60); g) a second phase detector (52) connected to said second amplifier (68); h) a second integrator (56) connected to said second phase detector (52) and to said second current monitor (60); i) a frequency source (40) connected to said first and second phase detectors (50, 52); and j) an amplifier and integrator (46), connected to said first and second resonant tunneling diodes (10, 11), for providing the precision voltage reference output (48).

Claim 21

Support electronics according to claim 16, 17 or 19, characterized by GaAs MESFET's and GaAs amplifiers.