For the current week, the overall ratings of 12 Semiconductor stocks are worse, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Rambus Inc. (NASDAQ:RMBS) ratings are on the decline this week as the company earns a F (“strong sell”). Last week, it received a D (“sell”). Rambus is a technology licensing company and focuses on the design, development and licensing of chip interface technologies and architectures that are foundational to nearly all digital electronics products. In Portfolio Grader’s specific subcategories of Earnings Revisions, Equity, Cash Flow, and Sales Growth, RMBS also gets F’s. The stock price has dropped 10.9% over the past month, worse than the 4.1% decrease the Nasdaq has seen over the same period of time. To get an in-depth look at RMBS, get Portfolio Grader’s complete analysis of RMBS stock.

This week, NVE Corp. (NASDAQ:NVEC) falls to a D (“sell”), worse than last week’s grade of C (“hold”). NVE Corporation is an electronics component manufacturer specializing in the combination of magnetically-sensitive materials with integrated circuits. The stock also gets an F in Sales Growth. Share prices fell 14.3% over the past month. For a full analysis of NVEC stock, visit Portfolio Grader.

ATMI (NASDAQ:ATMI) is having a tough week. The company’s rating falls from a C to a D rating. ATMI supplies materials, materials packaging, and materials delivery systems used worldwide in the production of microelectronics devices. The stock also rates an F in Margin Growth. Shares of the stock are changing hands at twice the rate they were a week ago. To get an in-depth look at ATMI, get Portfolio Grader’s complete analysis of ATMI stock.

The rating of United Microelectronics (NYSE:UMC) declines this week from a C to a D. United Microelectronics is a semiconductor wafer foundry that provides wafer fabrication services and technologies. The stock gets F’s in Earnings Growth, Earnings Momentum, and Cash Flow. Margin Growth and Sales Growth also get F’s. Investors seem to agree with the downgrade and have pushed down the share price 9.4% over the past month. For more information, get Portfolio Grader’s complete analysis of UMC stock.

MKS Instruments‘s (NASDAQ:MKSI) rating weakens this week, dropping to a D versus last week’s C. MKS Instruments provides instruments, subsystems, and process control solutions that measure, control, power, monitor, and analyze critical parameters to improve the process performance and productivity of advanced manufacturing processes. The stock gets F’s in Earnings Revisions and Sales Growth. For a full analysis of MKSI stock, visit Portfolio Grader.

TriQuint Semiconductor (NASDAQ:TQNT) earns a F this week, moving down from last week’s grade of D. TriQuint Semiconductor supplies communications companies with modules, components and foundry services. The stock gets F’s in Earnings Growth, Earnings Momentum, and Margin Growth. Wall Street appears to agree with the stock downgrade, with share prices dropping 6.4% over the past month. As of Oct. 30, 2012, 10.5% of outstanding TriQuint Semiconductor shares were held short. To get an in-depth look at TQNT, get Portfolio Grader’s complete analysis of TQNT stock.

This week, Tessera Technologies (NASDAQ:TSRA) drops from a C to a D rating. Tessera Technologies invests in, licenses and delivers miniaturization technologies for electronic devices. For a full analysis of TSRA stock, visit Portfolio Grader.

This is a rough week for Integrated Device Technology (NASDAQ:IDTI). The company’s rating falls to F from the previous week’s D. Integrated Device Technology designs, develops, manufactures, and markets a variety of semiconductor products and modules. In Earnings Growth, Earnings Momentum, Margin Growth, and Sales Growth the stock gets F’s. For more information, get Portfolio Grader’s complete analysis of IDTI stock.

Slipping from a C to a D rating, Nova Measuring Instruments (NASDAQ:NVMI) takes a hit this week. Nova Measuring Instruments develops, produces, and markets monitoring and measurement systems for the semiconductor manufacturing industry. The stock gets F’s in Earnings Growth, Earnings Momentum, and Sales Growth. Investors seem to agree with the downgrade and have pushed down the share price 3.5% over the past month. To get an in-depth look at NVMI, get Portfolio Grader’s complete analysis of NVMI stock.

The rating of ON Semiconductor (NASDAQ:ONNN) slips from a D to a F. ON Semiconductor supplies analog, standard logic, and discrete semiconductors for data and power management. The stock gets F’s in Earnings Growth, Margin Growth, and Sales Growth. For a full analysis of ONNN stock, visit Portfolio Grader.

Photronics (NASDAQ:PLAB) is having a tough week. The company’s rating falls from a C to a D rating. Photronics manufactures photomasks, which are high precision quartz plates that contain microscopic images of electronic circuits. The stock also gets an F in Sales Growth. Share prices fell 8.4% over the past month. As of Oct. 30, 2012, 10.2% of outstanding Photronics shares were held short. For more information, get Portfolio Grader’s complete analysis of PLAB stock.

LTX-Credence (NASDAQ:LTXC) experiences a ratings drop this week, going from last week’s D to a F. LTX-Credence designs, manufactures, and markets automatic test equipment for the semiconductor industry. The stock receives F’s in Earnings Growth, Earnings Momentum, and Equity. Margin Growth and Sales Growth also get F’s. For a full analysis of LTXC stock, visit Portfolio Grader.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.