A Radiation Hard MNOS CCD for Low Temperature Applications

P-buried channel charge-coupled devices (CCDs) with a 100 Å sio2 and 1.2 Å Si3N4 dual gate insulator have been fabricated and radiation tested. The CCDs are 105-and 150-bit 4-phase linear shift registers with double-level polysilicon gates. Most of the experimental data is obtained on p-buried channel devices because design considerations suggest that the p-buried channel structure will have the greatest tolerance to ionizing radiation for devices with MNOS gates. Threshold shifts on the order of -1 volt/106 rad(Si) have been achieved at both 80°K and 300°K on CCDs which are operated continuously during the irradiation. The p-buried channel CCDs show essentially no degradation in pre-irradiation transfer efficiency up to doses of 106 rad(Si) without any change in the operating biases.

[1]  R. L. Nielsen,et al.  Total Dose Effects of Ionizing Radiation on MOS Structures at 90°K , 1973 .

[2]  W. D. Baker,et al.  Effects of ionizing radiation on charge-coupled device structures , 1974 .

[3]  J. R. Srour,et al.  Leakage Current Phenomena in Irradiated SOS Devices , 1977, IEEE Transactions on Nuclear Science.

[4]  S. Wang,et al.  Low−temperature irradiation effects in SiO2−insulated MIS devices , 1975 .

[5]  B. L. Gregory,et al.  Process Optimization of Radiation-Hardened CMOS Integrated Circuits , 1975, IEEE Transactions on Nuclear Science.

[6]  R. Engelbrecht,et al.  DIGEST of TECHNICAL PAPERS , 1959 .

[7]  T. Chu,et al.  The preparation and C-V characteristics of SiSi3N4 and SiSiO2Si3N4 structures , 1967 .

[8]  K. Aubuchon,et al.  Radiation Hardening of P-MOS Devices by Optimization of the Thermal Si02 Gate Insulator , 1971 .

[9]  J. Killiany.  Low-Temperature Radiation Damage Effects in a Room-Temperature Radiation-Hard Surface Channel CCD , 1977, IEEE Transactions on Nuclear Science.

[10]  M. D. Fitzpatrick,et al.  Hardened MNOS/SOS Electrically Reprogrammable Nonvolatile Memory , 1977, IEEE Transactions on Nuclear Science.

[11]  H. E. Boesch.  Low Temperature Radiation Response of Al2O3 Gate Insulators , 1977, IEEE Transactions on Nuclear Science.

[12]  E. H. Nicollian,et al.  SURFACE STATES IN SILICON FROM CHARGES IN THE OXIDE COATING , 1968 .

[13]  W. F. Kosonocky,et al.  Fast-interface-state losses in charge-coupled devices. , 1972 .

[14]  N. Saks.  Response of MNOS Capacitors to Ionizing Radiation at 80°k , 1978, IEEE Transactions on Nuclear Science.

[15]  M. F. Tompsett,et al.  II-3 the effects of bulk traps on the performance of bulk channel charge-coupled devices , 1974 .

[16]  C.A.T. Salama.  Two-phase m.n.o.s. charge-coupled device , 1972 .

[17]  B. L. Gregory,et al.  Unified Model of Damage Annealing in CMOS, from Freeze-In to Transient Annealing , 1975, IEEE Transactions on Nuclear Science.

[18]  Radiation Hardened N-Buried Channel CCD's Using Backside Phosphorus Gettering , 1978, IEEE Transactions on Nuclear Science.