请给一段用silvaco仿真NPN晶体管的代码

下面是一个使用Silvaco仿真NPN晶体管的简单代码：

* This is a sample input file for the ATLAS simulator
* It simulates an NPN transistor with a base width of 1um

# Material definition
material Si
! Specify material properties here, such as permittivity, mobility, etc.

# Device definition
device npn
! Define the device structure here, including the doping profile, contact positions, etc.

# Simulation commands
solve
! Specify any simulation commands here, such as setting the temperature, convergence criteria, etc.

output iv
! Specify the type of output you want here, such as I-V curves, capacitance-voltage curves, etc.

请注意，这只是一个简单的示例代码，实际上在仿真NPN晶体管时需要更详细和复杂的输入文件。