Quantificational Dependence of Vertical Breakdown Voltage on Top Silicon and Dielectric Layer Thicknesses for SOI High Voltage Devices

摘要

The formula of silicon critical electric field ES,C is given as a function of silicon film thickness tS from an effective ionization rate α eff which is experimentally obtained by taking threshold energy ε T into accounting for electron multiplying. By the proposed ES,C, quantificational dependence of vertical breakdown voltage VB,V of SOI high voltage devices on top silicon thickness tS and dielectric layer thickness tI is discussed. For the same tS, a thicker tI brings on a higher VB,V because of a stated ES,C, VB,V=348V, 509V with tS=1 μ m for tI = 2 μ m, 3 μ m, respectively.For the same tI, VB,V increases with the decreasing of tS because of a crescent ES,C when tS is thin, and with tI=2 μ m, VB,V=852V, 348V for tS of 0.1 μ m and 1 μ m, respectively. So an ultra thin tS can be used to provide a high VB,V for SOI devicces. In addition, relation of tI on tS leading to the minimum of VB,V is given, which should be avoided when a SOI device is designed. 2-D simulative and some experimental results meet well with analytical results.