Non-uniform temperature and heat generation in thin-film SOI LDMOS with uniform drift doping

The thermal behaviour of lateral double-diffused MOS (LDMOS) transistors integrated in thin-film silicon-on-insulator is investigated in this work. This study is directed towards commercial LDMOS with uniformly doped drift regions. The presented models herein are suitable for electro-thermal predictions at conduction in the linear regime. Initially, a closed form expression is provided to calculate the Joule heat generated by electron current, which is spatially non-uniform. Then, the heat flow is analysed, thereby enabling simple LDMOS electro-thermal modelling and giving insight to improve device reliability. First principles of semiconductor physics are the fundamentals to develop the model, which requires the device structural parameters and the biasing conditions as inputs. Obtained temperature distributions and maximum temperature values are demonstrated to be more accurate than using the simple uniform heat generation approach.

[1]  M. Cheng,et al.  Analytical heat flow modeling of silicon-on-insulator devices , 2004 .

[2]  Il-Jung Kim,et al.  Analytical approach to breakdown voltages in thin-film SOI power MOSFETs , 1996 .

[3]  B. Murari.  Reliability of smart power devices , 1997 .

[4]  M. Asheghi,et al.  Thermal conductivity model for thin silicon-on-insulator layers at high temperatures , 2002, 2002 IEEE International SOI Conference.

[5]  M. Berger,et al.  Thermal time constants in SOI-MOSFETs , 1991, 1991 IEEE International SOI Conference Proceedings.

[6]  E. S. Schlig,et al.  Thermal properties of very fast transistors , 1970 .

[7]  Kambiz Vafai,et al.  Modeling of non-uniform heat dissipation and prediction of hot spots in power transistors , 1998 .

[8]  P. Palestri,et al.  Compact modeling of thermal resistance in bipolar transistors on bulk and SOI substrates , 2002 .

[9]  Siegfried Selberherr,et al.  High-voltage lateral trench gate SOI-LDMOSFETs , 2004, Microelectronics Journal.

[10]  Jaume Roig,et al.  Modeling of non-uniform heat generation in LDMOS transistors , 2005 .

[11]  M. Vellvehi,et al.  Study of novel techniques for reducing self-heating effects in SOI power LDMOS , 2002 .

[12]  Jerry G. Fossum,et al.  New physical insights and models for high-voltage LDMOST IC CAD , 1991 .

[13]  Denis Flandre,et al.  LDMOS in SOI technology with very-thin silicon film , 2004 .

[14]  Colin C. McAndrew,et al.  A four-terminal compact model for high voltage diffused resistors with field plates , 1998 .