Surface breakdown in silicon planar diodes equipped with field plate

Abstract The distribution of the electrical potential around the edge of the field plate in a silicon planar diode has been solved by means of a computer. The breakdown voltage related to this region has been derived as a function of impurity doping in silicon and of oxide thickness. If the oxide layer is not thick enough, avalanche breakdown voltage is often considerably lower than the value allowed by the material. The effect of Qss has been found to be negligible. Breakdown voltage vs. gate voltage measurement on gated diodes and avalanche light emission support an edge breakdown mechanism. Breakdown voltage on field plated diodes matches rather well with the calculated values. It normally drifts towards higher values and during this walkout a hot carrier current is collected by the field plate. The field plate current is fairly proportional to avalanche current and increases with bulk doping. A new planar diode structure suitable for a BV up to 900 V has been designed. The discharge voltage in air between field plate and equipotential ring (EQR) is shown to be correlated with the actual field at the edge.

[1]  G. L. Schnable,et al.  Behavior of surface ions on semiconductor devices , 1968 .

[2]  C. N. Berglund,et al.  AVALANCHE INJECTION CURRENTS AND CHARGING PHENOMENA IN THERMAL SiO2 , 1969 .

[3]  R. V. Overstraeten,et al.  Measurement of the ionization rates in diffused silicon p-n junctions , 1970 .

[4]  K. Lehovec,et al.  Charge motion on silicon oxide surfaces , 1967 .

[5]  J. Olivier,et al.  HOT ELECTRON EMISSION FROM SILICON INTO SILICON DIOXIDE BY SURFACE AVALANCHE , 1969 .

[6]  A. S. Grove,et al.  Surface effects on p-n junctions: Characteristics of surface space-charge regions under non-equilibrium conditions , 1966 .

[7]  Electrical Properties of Silicone Films on Silicon , 1969 .

[8]  J. Gillis,et al.  Matrix Iterative Analysis , 1961 .

[9]  H. Hara,et al.  A New Instability in MOS Transistor Caused by Hot Electron and Hole Injection from Drain Avalanche Plasma into Gate Oxide , 1970 .

[10]  G. A. Baraff,et al.  Distribution Functions and Ionization Rates for Hot Electrons in Semiconductors , 1962 .

[11]  R. A. Logan,et al.  Ionization Rates of Holes and Electrons in Silicon , 1964 .

[12]  D. Speeney,et al.  Experimental study of the effect of junction curvature on breakdown voltage in Si , 1967 .

[13]  N. I. Meyer,et al.  Hot-Electron Emission From Shallow p-n Junctions is Silicon , 1963 .

[14]  G. Gibbons,et al.  Effect of junction curvature on breakdown voltage in semiconductors , 1966 .

[15]  A. S. Grove,et al.  Effect of surface fields on the breakdown voltage of planar silicon p-n junctions , 1967 .

[16]  W. Shockley,et al.  Mobile electric charges on insulating oxides with application to oxide covered silicon p-n junctions☆ , 1964 .