Abstract A novel technique is disclosed for radiation hardening of MOS devices and specifically for stabilizing the gate threshold potential at room temperature of a radiation subjected MOS fieldeffect device of the type having a semiconductor substrate, an insulating layer of oxide on the substrate, and a gate electrode disposed on the insulating layer. In the preferred embodiment, the novel inventive technique contemplates the introduction of boron into the insulating oxide, the boron being introduced within a layer of the oxide of about 100A-300A thickness immediately adjacent the semiconductor-insulator interface. The concentration of boron in the oxide layer is preferably maintained on the order of 1018atoms/cm3. The novel technique serves to reduce and substantially annihilate radiation induced positive gate charge accumulations, which accumulations, if not eliminated, would cause shifting of the gate threshold potential of a radiation subjected MOS device, and thus render the device unstable and/or inoperative.
A MOS FIELD-EFFECT DEVICE EXHIBITING A REDUCED GATE THRESHOLD POTENTIAL SHIFT SENSITIVITY TO IONIZING RADIATION, SAID DEVICE COMPRISING A SUBSTRATE OF SEMICONDUCTOR MATERIAL, A GATE ELECTRODE, AN INSULATING FILM OF OXIDE DISPOSED BETWEEN SAID GATE ELECTRODE AND SAID SEMICONDUCTOR SUBSTRATE, AND ELEMENT MEANS IN SAID OXIDE FILM DISPOSED ONLY AT THE SEMICONDUCTOR-INSULATOR INTERFACE PROVIDING ACCEPTORS IN THE SEMICONDUCTOR LATTIC, SAID ELEMENT MEANS SUBSTANTIALLY ANNIHILATING
Claim 2
Dependent Claim
64 words
A MOS FIELD-EFFECT DEVICE EXHIBITING A REDUCED GATE THRESHOLD POTENTIAL SHIFT SENSITIVITY TO IONIZING RADIATION, SAID DEVICE COMPRISING A SUBSTRATE OF SEMICONDUCTOR MATERIAL, A GATE ELECTRODE, AN INSULATING FILM OF OXIDE DISPOSED BETWEEN SAID GATE ELECTRODE AND SAID SEMICONDUCTOR SUBSTRATE, AND ELEMENT MEANS IN SAID OXIDE FILM DISPOSED ONLY AT THE SEMICONDUCTOR-INSULATOR INTERFACE PROVIDING ACCEPTORS IN THE SEMICONDUCTOR LATTIC, SAID ELEMENT MEANS SUBSTANTIALLY ANNIHILATING
Claim 3
Dependent Claim
12 words
The device defined in claim 1, wherein said element means comprises boron.
Claim 4
Dependent Claim
27 words
The device defined in claim 2, wherein said boron is disposed in a layer of said oxide of about 100A-300A thickness only immediately adjacent the semiconductor-insulator interface.
Claim 5
Dependent Claim
17 words
The device defined in claim 3, wherein the concentration of boron is on the order of 1018atoms/cm3.
Claim 6
Dependent Claim
19 words
The device defined in claim 4, further including source and drain regions on said substrate and electrodes associated therewith.