Heat Generation and Transport in Submicron Semiconductor Devices

• Published in: Journal of heat transfer 1995-02, Vol.117 (1), p.25-31
• Main Authors: Fushinobu, K, Majumdar, A, Hijikata, K
• Format: Article
• Language: English
• Subjects: Applied sciences; Electronics; Exact sciences and technology; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors
• ISSN: 0022-1481; 1528-8943
• DOI: 10.1115/1.2822317

The reduction of semiconductor device size to the submicrometer range leads to unique electrical and thermal phenomena. The presence of high electric fields (order of 107 V/m) energizes the electrons and throws them far from equilibrium with the lattice. This makes heat generation a nonequilibrium process. For gallium arsenide (GaAs), energy is first transferred from the energized electrons to optical phonons due to strong polar coupling. Since optical phonons do not conduct heat, they must transfer their energy to acoustic phonons for lattice heat conduction. Based on the two-step mechanism with corresponding time scales, a new model is developed to study the process of nonequilibrium heat generation and transport in a GaAs metal semiconductor field effect transistor (MESFET) with a gate length of 0.2 μm. When 3 V is applied to the device, the electron temperature rise is predicted to be more than 1000 K. The effect of lattice heating on electrical characteristics of the device shows that the current is reduced due to decrease in electron mobility. The package thermal conductance is observed to have strong effects on the transient response of the device.