Patent ID: 6936907
Filing Date: 2005-08-30
Classification: H01L

Abstract:
1. A surface voltage-sustaining region for semiconductor devices, said semiconductor devices have a semiconductor substrate of a first-conductivity type and a largest potential region made by a metal or by a heavily doped semiconductor of a second-conductivity type and a smallest potential made by a metal or by a heavily doped semiconductor region of a first-conductivity type, said largest potential region and said smallest potential region are contacted with the substrate, said surface voltage-sustaining region is located on the top of the substrate and from the largest potential region to the smallest potential region, wherein: said surface voltage-sustaining region has at least one section which has a thin film of high permittivity dielectric covered on the semiconductor surface; said thin film of high permittivity dielectric may have one or multiple section(s) where conductor is covered on its top, the conductor can be electrically floating or electrically connected to a voltage terminal outside of surface voltage-sustaining region; said surface voltage-sustaining region can also have one or multiple section(s) of second conductivity type and/or first conductivity type semiconductor layer with doping concentration(s) and/or conductivity type different from that of the substrate; said surface voltage-sustaining region transmit a net average electric flux of first sign everywhere to the substrate when a reverse voltage close to the breakdown voltage is applied across the largest potential region and the smallest potential region, the effective average flux density starts from a value about qN said electric flux of first sign means the flux has the same sign of the flux produced by the ionized impurity of the semiconductor of the second conductivity type; said net average electric flux of the first sign means the average electric flux of the first sign subtracting the average electric flux of the second sign, where second sign is opposite to the first sign; under the action of said net average flux of the first symbol, the surface (lateral) field in said surface voltage-sustaining region has its minimum value close to zero from the position close to the region having the largest potential and increases its magnitude when the position is close to the region having the smallest potential; said electric flux density includes the flux density produced by the ionized impurities in the thin semiconductor layer of the surface voltage-sustaining region as well as the flux density introduced by the thin film of high permittivity dielectric at the surface; said flux density introduced by the thin film of high permittivity dielectric at the surface means the flux density introduced by a thin film of high permittivity dielectric with or without a conductor covered on its top, wherein: