CAD Approach to Control High-Temperature Processes in SiC Technology

Andrzej Kubiak,Ewa Raj,Zbigniew Lisik

doi:10.3390/electronics11050768

Abstract

Manufacturing silicon carbide semiconductor devices may require high-temperature treatment in closed graphite reactors. This makes temperature control of processed SiC substrates difficult, since their temperature cannot be measured directly. As the monitoring of the SiC sample temperature is critically important for proper process flow, an indirect method involving the use of the CAD approach has been developed. A numerical model of a furnace reactor was created on the basis of the commercial ANSYS package, allowing for the simulation of thermal fields under given heat-dissipation conditions in the modeled area and in the presence of gaseous and liquid media participating in heat exchange and transport. Obtained simulation results remain very consistent with the reference temperature measurements of selected areas of the reactor. The model acts as an accurate tool for temperature distribution verification during the high-temperature annealing of and diffusion of dopants for silicon carbide.

Highlights

Silicon is still the dominant semiconductor material in microelectronics, its physical limitations are more and more visible, keeping the parameters of manufactured devices from meeting the current expectations of the market
The large band gap makes possible the manufacturing of low-noise devices or devices working at high temperatures exceeding even 700 ◦C [6–8], as well as optoelectronics devices for “blue optoelectronics” [9,10]
This paper presents the construction details of the Degussa furnace reactor with an additional cassette for SiC processing, which was the starting point for the creation of a numerical model of the phenomena occurring in the reactor during high-temperature processes, as well as the subsequent stages of CAD model development and verification of taken assumptions

Summary

Introduction

Silicon is still the dominant semiconductor material in microelectronics, its physical limitations are more and more visible, keeping the parameters of manufactured devices from meeting the current expectations of the market. The investigations are focused on wide bandgap (WBG) semiconductors, whose physical parameters exceed the silicon ones. They are characterized by larger band gaps, higher melting temperatures, better heat conductivity, a larger electron saturation velocity and greater critical electric field strength. The large band gap makes possible the manufacturing of low-noise devices or devices working at high temperatures exceeding even 700 ◦C [6–8], as well as optoelectronics devices for “blue optoelectronics” [9,10]. The large saturation electron velocity makes them an excellent candidate for high-frequency devices with possible maximal frequencies reaching THz [11,12]. Good thermal conductivity is very crucial from a reliability point of view (thermal stresses) and for thermal-management problems [7]

Methods

Findings

Discussion

Conclusion