Self-Heating Investigation in SOI MOSFET Structures with High Thermal Conductivity Buried Insulator Layers

The self-heating of thin and short silicon on insulator (SOI) devices is a serious problem limiting operation and reducing device lifetime. The main source of this phenomenon is low thermal conductivity of SiO
₂
buried oxide (λSiO2=1.4W/m·K 100 time lower than that of silicon λSi=140W/m·K). In this work three novel buried oxide (BOX) configurations in SOI MOSFET structure which suppress the self-heating effect are analyzed: 1) ultra-thin SiO
₂
BOX; 2) buried layers with high thermal conductivity material AlN, Al
₂
O
₃
, Si
₃
N
₄
; 3) stack of traditional SiO
₂
BOX with AlN plug. TCAD was used to study the 2D temperature distribution in device structures. The simulation results show that the thermal dissipation and self-heating were dramatically improved in all the devices. The UTB and UTBB ultra-thin SiO
₂
BOXes reduce the maximum internal device temperature 25 K and 39 K lower than that of normal SiO
₂
BOX; AlN, Al
₂
O
₃
, Si
₃
N
₄
BOXes reduce Tmax by 31-24 K lower than that of SiO
₂
BOX. The advantages and difficulties in practical use of the SOI MOSFETs with novel buried insulator layers are discussed.