3.5. Specify the Heater Conditions

The LPCVD Thermal Analyzer allows the heater boundary conditions to be specified either as heater powers or heater temperatures by using either the SPECIFY THE HEATER POWERS keyword block or the SPECIFY THE HEATER TEMPERATURES keyword block. The LPCVD Thermal Analyzer only allows one of these two keyword blocks to be used in the input. If heater powers are entered, then the model determines the heater temperatures as part of the solution.

Table 3.5: SPECIFY THE HEATER CONDITIONS Keyword Phrases

Keyword Phrase

Description

SPECIFY THE HEATER POWERS

Title of keyword block used to specify the powers applied to the heaters as an alternative to specifying heater temperatures using the SPECIFY THE HEATER TEMPERATURES keyword block. A series of up to 10 heating zones are specified by giving the beginning axial location, ending axial location, and applied power. The axial locations are given relative to the entrance of the quartz tube (see Figure 3.2: Definition of input parameters for the model included in the SPECIFY THE REACTOR keyword block ). Heater zone numbers must be specified in order of increasing . If this keyword block is used, none of the keywords in the block have defaults; all are required inputs. Requires END statement to close keyword block.

ZBEG(#) =

Provides the beginning axial location of the specified (# ≤ 10) heating zone in the reactor relative to the beginning of the quartz tube. Heater zone numbers must be specified in order of increasing . Part of the SPECIFY THE HEATER POWERS keyword block.

Example: ZBEG(1) = 38.45ZBEG(2) = 63.55

Units: cm

ZEND(#) =

Provides the ending axial location of the specified (# ≤ 10) heating zone in the reactor relative to the beginning of the quartz tube. Heater zone numbers must be specified in order of increasing . Part of the SPECIFY THE HEATER POWERS keyword block.

Example: ZEND(1) = 63.54ZEND(2) = 93.34

Units: cm

POWER(#) =

Provides the power applied to the specified (# ≤ 10) heating zone in the reactor. Heater zone numbers must be specified in order of increasing . Part of the SPECIFY THE HEATER POWERS keyword block.

Example: POWER(1) = 400.0POWER(2) = 400.0

Units: W

SPECIFY THE HEATER TEMPERATURES

Title of keyword block used to specify the temperatures at certain points in the heaters as an alternative to specifying heater powers using the SPECIFY THE HEATER POWERS keyword block. A series of up to 10 temperature points are specified by giving the axial location and corresponding temperature. Temperature point numbers must be specified in order of increasing . The LPCVD Thermal Analyzer uses linear interpolation between the specified points to determine the heater temperature at grid points. If this keyword block is used, none of the keywords in the block have defaults; all are required inputs. Requires END statement to close keyword block.

Z(#) =

Provides the axial location of the specified (# ≤ 10) temperature point in the heater, relative to the beginning of the quartz tube. Temperature point numbers must be specified in order of increasing . Part of the SPECIFY THE HEATER TEMPERATURES keyword block.

Example: Z(1) = 38.45Z(2) = 63.54

Units: cm

T(#) =

Provides the temperature at the specified (# ≤ 10) temperature point in the heater. Temperature point numbers must be specified in order of increasing . Part of the SPECIFY THE HEATER TEMPERATURES keyword block.

Example: T(1) = 873.15T(2) = 873.15

Units: K