Choosing the Right Semiconductor Materials for Your Dev Board

Silicon semiconductor materials with microcircuits

Some metals and nonmetals possess properties that make them attractive materials for PCBA manufacturing. For example, circuit board traces almost always are made of transition metal copper (Cu), an excellent conductor. PCB stackups include copper sheets for signal and carbon-based weaves that act as good insulators for prepreg and cores. For components, semiconductor materials with conductivities that fall between that of most conductors and insulators are by far the most utilized.

Let’s take a look at some commonly used semiconductor materials, their benefits, and how they can influence your development board design.

Semiconductor Materials: Why They Are Important

Researchers have studied semiconductor materials and many of their unique characteristics since the 19th century. Karl Braun is credited with discovering the “diode effect” in 1874. This unidirectional current flow is a signature property of the myriad semiconductor devices in use today. Other properties leveraged to create semiconductor devices include the following:

Semiconductor Properties

• Controllable electrical conductivity

The amount of current flow through a semiconductor device can be set and controlled by adding impurities (doping) or exposing the device to an electric field (gating).

• Generation and recombination

For some semiconductor materials, the introduction of light will generate electrons through the photovoltaic effect. Conversely, electrons can recombine with holes and generate light. This generation and recombination of electrons and holes is a fundamental operating function of optoelectronic devices.  

• Thermal energy conversion

Semiconductors generate heat from an electrical potential difference across the device. Peltier and Seebeck devices depend on this characteristic. 

• Light emission

Materials can emit light instead of heat when returning to thermal equilibrium. For example, components in LED lighting systems contain these kinds of materials.

The semiconductor properties listed above have led to the design and production of a wide range of semiconductor components.

Common Semiconductor Devices

• Diode 
  • Rectifier
  • Pin
  • Gunn
  • Laser
  • LED
  • Schottky
  • Zener 
  • Photo
• Transistor
  • Bipolar (BJT)
  • Junction Field Effect (JFET)
  • Metal Oxide Semiconductor Field Effect (MOSFET)
  • Insulated-Gate Bipolar Transistor (IGBT)
  • Photo
• Optocoupler

Semiconductor materials and the components derived from them are critical for most PCBA designs, including evaluation and development boards.

Selecting Semiconductor Materials for Your Dev Board

Semiconductors are an integral component in electronic manufacturing. And while silicon is by far the most used semiconductor material, there are alternative semiconductor materials, as shown in the table below. 

Comparison of semiconductor material properties

The table above illustrates the variation in the electrical properties of commonly used semiconductor materials found in electronic components. As shown, your choice of semiconductor component can indeed impact the electrical performance of your development board. The considerations listed below should also factor into your component selection decision.

Considerations for Choosing Semiconductor Materials for Development Boards

• Electrical properties

Electrical properties such as doping limits, thermal conductivity and bandgap energy all impact the voltage and current levels at which the device and board will operate.

• Thermal properties

Semiconductor temperature and resistivity are inversely proportional. A semiconductor can produce high heat that impacts PCB layout and thermal dissipation and distribution.

• Moisture sensitivity

Some components are more sensitive to moisture than others, which can affect manufacturing. For example, post-assembly baking or coating may be required. This parameter can also influence packaging, storage and other moisture protection methods.